1 tablespoon lemon zest, or the zest of (1) large lemon
2 tablespoons fresh lemon juice
2 teaspoons vanilla extract
1 cup all-purpose flour (see note below for gluten-free alternative)
1/2 teaspoon baking powder
1/2 cup sour cream
6 ounces fresh blueberries, or about 1 cup's worth
2/3 cup all-purpose flour, or 2/3 cup brown rice flour
1/3 cup brown sugar
1/4 cup melted butter
Preheat the oven to 350 degrees. Grease an 8" square pan with butter. Beat the butter and the sugar together until light and fluffy, about 6-7 minutes. Stir in the vanilla, lemon zest, lemon juice. Add the eggs one at a time, mixing just until combined.
Combine the flour and baking powder in a bowl. Place the blueberries in a small bowl and sprinkle with a couple tablespoons of the dry ingredients, stir gently to coat the berries. Add half of the dry ingredients to the mixing bowl and stir to combine. Add the sour cream, mix again, and add the remaining dry ingredients. Mix just until combined.
Gently stir in the blueberries and pour the batter into the prepared pan. Place the flour and sugar for the topping in the same small bowl that was holding the berries and add the melted butter. Stir lightly with a fork to combine. Sprinkle the sugary crumbs over the batter in the pan.
Bake for 40-45 minutes, untilÂ a toothpick comes out clean or with moist crumbs. Let cool before slicing. Enjoy!