Preheat oven to 350°F.

Line a loaf pan with parchment paper and lightly spray with baking spray.

Whisk together flour, baking powder, salt, and lemon zest in a medium bowl. Set aside.

In a stand mixer, or using a hand mixer, beat together butter, granulated sugar, and brown sugar until light and fluffy.

Add sour cream, lemon juice, and vanilla bean paste to the butter and sugar mixture and beat until smooth.

Add eggs one at a time, beating lightly and scraping down the bowl after each addition.

Beat 1–2 minutes after all eggs are added to fully incorporate.

Fold flour mixture into the wet ingredients gently until just combined. Do not overmix.

Pour batter into prepared loaf pan.

Bake for 60-70 minutes, or until a toothpick in the center comes out clean.

If loaf is browning too fast, cover loosely with foil after 45 min.

In a small saucepan, combine water, sugar, and lemon juice. Bring to a boil, then reduce heat and simmer 2–3 min until sugar dissolves. Set aside to cool.

When loaf comes out of oven, brush generously with lemon syrup while still warm. This locks in moisture and enhances lemon flavor. (It will seem like there is too much syrup, but it will be absorbed by the cake to create the most moist loaf).

Mix powdered sugar, lemon juice, milk, and vanilla in a small bowl until smooth. Adjust consistency with more juice or sugar if needed.

Once the loaf is cooled to room temperature, drizzle or spoon glaze over the top.

Let glaze set slightly before slicing.

Slice and enjoy a moist, tender, bright lemon loaf.