• 1 cup unsalted butter, melted
• 1 1/2 cups granulated sugar
• 3 large eggs
• 1/2 cup sour cream
• 2 tablespoons lemon zest
• 1 teaspoon vanilla extract
• 1 1/2 cups all-purpose flour
• 1/2 cup cornstarch
• 1/2 teaspoon baking powder
• 1/4 teaspoon salt
• 1/2 cup powdered sugar
1. Preheat your oven to 350°F (180°C). Line a 9×9-inch square baking pan with parchment paper.
2. In a large mixing bowl, whisk together the melted butter and granulated sugar until well combined.
3. Add the eggs, sour cream, lemon zest, and vanilla extract to the bowl and mix until well combined.
4. In a separate bowl, whisk together the flour, cornstarch, baking powder, and salt. Add the dry ingredients to the wet ingredients and mix until just combined. Do not overmix.
5. Pour the brownie batter into the prepared baking pan and smooth the top with a spatula.
6. Bake the brownies for 25-30 minutes, or until a toothpick inserted into the center comes out clean.
7. Let the brownies cool in the pan for 10 minutes, then use the parchment paper to lift them out of the pan and transfer them to a wire rack to cool completely.
8. Once the brownies are cool, sift the powdered sugar over the top. Cut the brownies into squares and serve.