Quiche has always been a family staple in our house. It’s one of those recipes that works for just about everything—breakfast, brunch, lunch, an easy dinner, or even meal prep for the week. I love how versatile it is because you can easily change the vegetables, cheeses, and herbs depending on what’s in season or what you have on hand. In fact, my children love it so much that it is one of the only ways they get their vegetables sometimes!
This Caramelized Onion and Zucchini Quiche is one of my personal favorites. Sweet, deeply caramelized onions pair beautifully with fresh zucchini, creamy mozzarella, Parmesan cheese, and a rich, silky egg custard, all baked inside a flaky pie crust. It’s simple enough for a weeknight dinner but elegant enough for holidays, bridal showers, Mother’s Day brunch, or weekend entertaining.
Whether you use a store-bought pie crust for convenience or homemade pie dough (my favorite!), this quiche always turns out delicious. During zucchini season, it’s one of the recipes I find myself making again and again. And now you will too!
Why you’ll love this recipe!
What ingredients do I need?
- Homemade, or Prepared, Pie Crust: A flaky pie crust creates the perfect base for this quiche. Store-bought pie dough works wonderfully when you’re short on time, while homemade pie dough adds an extra-special touch if you have it on hand.
- Eggs: Whole eggs provide structure and help create the classic custard texture every great quiche needs.
- Egg Yolks: Extra yolks make the filling richer, creamier, and more luxurious.
- Heavy Cream: Heavy cream creates a silky, smooth custard that bakes beautifully and gives the quiche its rich texture.
- Zucchini: Fresh zucchini adds color, moisture, and a mild flavor that pairs perfectly with the caramelized onions. Be sure to squeeze out as much liquid as possible before mixing it into the filling.
- Sweet Onion: Cooking the onions low and slow transforms them into soft, golden ribbons with incredible sweetness that balances the zucchini beautifully.
- Unsalted Butter, or Olive Oil: Used to slowly caramelize the onions while adding rich flavor.
- Mozzarella Cheese Block: Freshly shredded mozzarella melts into creamy pockets throughout the quiche without overpowering the vegetables.
- Parmesan Cheese: Freshly grated Parmesan adds a salty, nutty flavor that enhances every bite.
- Garlic Powder: Adds savory garlic flavor throughout the custard.
- Dried Parsley: Brings subtle herb flavor and color.
- Kosher Salt: Enhances every ingredient while balancing the richness.
- Black Pepper: Adds just enough warmth to round out the filling.
- Fresh Basil (Optional Garnish): A sprinkle of fresh basil adds brightness and pairs beautifully with the zucchini.
Recipe Variations
- Meat Lovers: Add cooked bacon, pancetta, or breakfast sausage.
- Veggie Lovers: Stir in sautéed mushrooms, roasted red peppers, sun-dried tomatoes, sautéed and drained spinach or kale, and/or roasted garlic.
- Switch up the cheese: Replace the mozzarella with Gruyère for a more French-inspired version.
Pro Tips
- Shred the zucchini using the large holes of a box grater. Larger shreds provide the best texture and won’t disappear into the custard. They also release moisture more easily when squeezed dry, resulting in a better finished quiche.
- Salt the zucchini before squeezing out as much moisture as possible. After shredding the zucchini, I like to place it in a colander lined with a clean kitchen towel and sprinkle it lightly with salt. Let it sit for about 10 minutes before gathering the towel and squeezing out as much liquid as possible. The salt helps draw excess moisture out of the zucchini, resulting in a thicker, creamier custard and preventing a watery quiche.
- Blind bake the crust for the crispiest results (optional). Because zucchini naturally releases moisture as it bakes, blind baking can help prevent a soggy bottom crust. That said, I’ll be honest, I typically skip this step (espeically when short on time) and the quiche still turns out delicious. But if you want an extra flaky, crisp crust, then it’s worth the few extra minutes.
- How to blind bake: Place the pie dough in your pie dish, crimp the edges, and dock the bottom with a fork. Line the crust with parchment paper and fill it with pie weights or dried beans. Bake at 425°F for 12–15 minutes, then carefully remove the parchment and weights. Return the crust to the oven for another 3–5 minutes, just until the bottom looks dry but not browned. Add the filling and continue with the recipe as directed.
- Take your time caramelizing the onions. Low and slow is the key here. Cooking the onions for 30–40 minutes on medium-low allows their natural sugars to develop, creating a rich, sweet flavor that balances the savory custard beautifully. Don’t rush this step, it makes all the difference.
- Use freshly grated Parmesan whenever possible. Freshly grated Parmesan melts more smoothly, has a richer flavor, and doesn’t contain the anti-caking agents often found in pre-shredded cheese.
- Don’t overmix the custard. Whisk the eggs and cream together just until smooth. Overmixing can incorporate too much air, which may cause the quiche to puff up in the oven and sink more as it cools.
- Let the caramelized onions cool slightly before adding them to the eggs. This helps prevent the hot onions from beginning to cook the eggs before the quiche goes into the oven.
- Bake until the center is just set. The edges should be firm while the very center still has a slight jiggle when you gently shake the pan. The residual heat will continue cooking the custard as it rests, giving you the perfect silky texture.
- Let the quiche rest before slicing. Allow it to cool for at least 10–15 minutes after baking. This gives the custard time to fully set, making it much easier to slice cleanly while also improving the overall texture.
- Protect the crust from overcooking if needed. If the edges begin browning too quickly during baking, loosely cover them with strips of aluminum foil or a pie shield for the remainder of the bake.
- Enjoy it warm, room temperature, or cold. One of the best things about quiche is how versatile it is. It’s delicious fresh from the oven, but the flavors continue to develop as it chills, making leftovers just as enjoyable the next day.
Can I Substitute?
Yes! Like always though, any substitutions made to the recipe can result in a change in texture and/or flavor.
- Mozzarella Cheese: Substitute Gruyère, fontina, Swiss, or sharp white cheddar for the mozzarella.
- Zucchini: Yellow squash works well in place of zucchini.
- Heavy Cream: Whole milk may be substituted for heavy cream, though the filling won’t be quite as rich.
- Sweet Onion: Red onions can be substituted for sweet onions.
- Olive oil or unsalted butter both work well for caramelizing the onions, however I do prefer the butter for this recipe.
- Use your favorite homemade or store-bought pie crust.
Dietary Substitutions
- Vegetarian: As written.
- Gluten-Free: Use your favorite gluten-free pie crust.
- Low-Carb: Skip the crust and bake the filling in a greased pie dish.
- Higher Protein: Add your favorite protein, like cooked turkey sausage, bacon, or diced ham.
Leftovers and Storage
- Refrigerator: Store leftover quiche tightly covered in the refrigerator for up to 4 days.
- Freezer:
- Individual slices: Cool completely, wrap individual slices tightly in plastic wrap and foil, then freeze for up to 3 months.
- Whole pie: Wrap the cooled whole quiche tightly in plastic wrap and foil, then freeze for up to 3 months. Thaw overnight in the refrigerator and reheat in a 325°F oven until hot.
- Reheating: Warm slices in a 325°F oven for 10–15 minutes, or microwave gently until heated through.
- Serving:This quiche is just as delicious warm, room temperature, or chilled straight from the refrigerator.
But, I Still Have A Few Questions…
Can I make this zucchini quiche ahead of time?
Absolutely! Quiche is one of my favorite make-ahead meals. Bake it up to 2 days in advance, refrigerate, then gently reheat before serving or enjoy it cold.
How do I keep zucchini quiche from becoming watery?
Zucchini holds a lot of water, so it’s important to squeeze it very dry after shredding. Using a clean kitchen towel or cheesecloth works best and helps create a rich, creamy custard.
How do you drain zucchini for quiche?
After shredding the zucchini, place it in a colander lined with a clean kitchen towel or cheesecloth. Sprinkle it lightly with salt and let it rest for about 10 minutes. The salt helps pull excess moisture from the zucchini. Once it’s rested, gather the towel and squeeze firmly until as much liquid as possible has been removed before adding the zucchini to the filling.
Why do you salt the zucchini first?
Zucchini naturally contains a lot of water. Sprinkling it with a little salt helps draw out that excess moisture through osmosis, making it much easier to squeeze dry. Removing as much liquid as possible prevents a watery quiche and helps create a rich, creamy custard with the perfect texture.
Do I have to blind bake the crust?
No! I often skip this step just for convenience, especially on busy weeknights, and the quiche is still delicious. However, if you prefer an extra crisp, flaky bottom crust, blind baking is a great option, especially since zucchini contains quite a bit of moisture.
How do I blind bake a pie crust for quiche?
Place the pie dough into your pie dish, crimp the edges, and prick the bottom several times with a fork. Line the crust with parchment paper and fill it with pie weights or dried beans. Bake at 425°F for 12–15 minutes, then carefully remove the parchment and weights. Return the crust to the oven for another 3–5 minutes, or until the bottom looks dry but isn’t browned. Fill and bake the quiche as directed in instructions.
Can I use homemade pie dough?
Yes! Homemade pie dough is my favorite for this recipe when I have the time, but a quality store-bought pie crust works beautifully and makes this recipe even easier.
Can I use milk instead of heavy cream?
Yes. Whole milk can be substituted, though heavy cream creates a richer, silkier custard.
Can I make this crustless?
Absolutely! Simply pour the filling into a greased pie dish and bake until set.
What cheeses work best in zucchini quiche?
Mozzarella keeps the filling creamy, while Parmesan adds salty, savory flavor. Gruyère, fontina, Swiss, or white cheddar are all delicious substitutions.
Can I freeze quiche?
Yes! Allow it to cool completely, wrap individual slices tightly, and freeze for up to 3 months. Thaw overnight in the refrigerator before reheating.
Can I freeze the whole quiche?
Absolutely! After baking, let the quiche cool completely, then wrap the entire quiche tightly in plastic wrap followed by aluminum foil. Freeze for up to 3 months. When ready to enjoy, thaw it overnight in the refrigerator, then bake at 325°F for 20–30 minutes, or until warmed through. If needed, cover the edges of the crust with foil to prevent over-browning.
Can I eat quiche cold?
Definitely! Quiche is delicious warm, room temperature, or straight from the refrigerator, making it perfect for meal prep and packed lunches.
How do I know when my quiche is done?
The edges should be set while the very center still has a slight jiggle. It will continue setting as it cools.
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Let’s engage!
Make sure to tag @thehomechefmomma on Instagram or Facebook, and leave a review or comment if you make these. I always get so excited to see your creations, variations of the recipe, and feedback! Just remember to be kind in your comments, there is still a person behind this screen! 🙂
Caramelized Onion and Zucchini Quiche
Ingredients
Filling
- 2 large eggs
- 4 large egg yolks
- 1 cup heavy cream
- 2 medium zucchini shredded and squeezed very dry (about 2 cups after draining)
- 1 large sweet onion thinly sliced
- 1 tablespoon unsalted butter, or olive oil
- 8 ounces fresh mozzarella shredded or torn into pieces
- ½ cup freshly grated Parmesan cheese
- 1 teaspoon garlic powder
- 1 teaspoon dried parsley
- 1 teaspoon kosher salt
- ½ teaspoon freshly cracked black pepper
Optional Garnish
- Fresh basil
- Additional grated Parmesan
Instructions
- Preheat the oven to 425°F.
- Place the pie crust into a 9-inch pie dish. Crimp the edges and dock the bottom with a fork. Set aside
- Heat the butter in a skillet over medium-low heat. Add the onions with a pinch of salt and cook for 30–40 minutes, stirring occasionally, until deeply golden and caramelized. Let cool slightly.
- Shred the zucchini and squeeze out as much moisture as possible using a clean kitchen towel.
- In a large bowl, whisk together the eggs, egg yolks, heavy cream, garlic powder, parsley, salt, and pepper.
- Fold in the zucchini, caramelized onions, mozzarella, and Parmesan.
- Pour the filling into the prepared crust.
- Bake at 425°F for 20 minutes, then reduce the oven temperature to 350°F and bake another 30 minutes, or until the center is just set.
- If the crust browns too quickly, loosely cover the edges with foil.
- Let the quiche cool for 10–15 minutes before slicing.
- Garnish with fresh basil and additional Parmesan, if desired.
Notes
- Drain the zucchini well. Place the shredded zucchini in a towel-lined colander, sprinkle lightly with salt, and let it rest for 10 minutes before squeezing out as much liquid as possible.
- Caramelize the onions low and slow. Taking the time to caramelize the onions develops a rich, sweet flavor that makes this quiche extra special.
- If you want a crispier crust, blind bake it first. This helps keep the bottom crust crisp and flaky, even with the moisture from the zucchini.
- Let the quiche rest before slicing. Cooling for 10–15 minutes allows the custard to fully set for clean, beautiful slices.
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Wondering where the pie crust recipe might be found, please?
Hello! This recipe works well with premade store-bought pie dough, or homemade. I did link the recipe for my homemade version in the blog post itself, or you can search for it by typing “pie dough” in the search bar! I hope this helps. -Jenn