Preheat your oven to 250°F. Line a large baking sheet with parchment paper.
Cut the bread into approximately ½-inch cubes, keeping the pieces as uniform as possible for even baking.
Place the bread cubes in a large mixing bowl. Drizzle with the extra virgin olive oil.
Sprinkle with Trader Joe's Onion Salt or the homemade seasoning blend. Toss thoroughly until the bread cubes are evenly coated with oil and seasoning.
Spread the seasoned bread cubes in a single, even layer on the prepared baking sheet, leaving a little space between the pieces.
Bake at 250°F for approximately 30–40 minutes, stirring once or twice during baking, until the croutons are dry, crunchy, and lightly golden. Baking time may vary depending on the type of bread and size of the cubes.
Remove the baking sheet from the oven and allow the croutons to cool completely. They will continue to crisp up as they cool.
Enjoy immediately on salads or soups, or transfer to an airtight container once completely cooled.