Instructions

• Preheat the oven to 350°F (175°C). Line an 8-by-8-inch baking pan with aluminum foil and spray the foil with cooking spray; set the prepared pan aside.
• In a large bowl, whisk together 1 1/4 cups all-purpose flour, 3/4 cup granulated sugar, 2 teaspoons baking powder, and a pinch of salt if using.
• Add 1 tablespoon lemon zest to the dry ingredients and whisk to combine; set the dry mixture aside.
• In a separate bowl, whisk together 1 large egg, 1/2 cup buttermilk, 1/3 cup sour cream, 1/4 cup lemon juice, 3 tablespoons oil, and 2 teaspoons lemon extract until smooth.
• Pour the wet mixture into the dry mixture. Stir gently with a spoon or fold with a spatula until just combined — small lumps are fine. Do not overmix.
• Transfer the batter to the prepared pan and smooth the top lightly. Bake for about 28 to 31 minutes, or until the center is set and a toothpick inserted in the center comes out clean or with a few moist crumbs.
• Remove the pan from the oven and place it on a wire rack. Let the cake cool in the pan while you make the glaze.
• In a medium bowl, whisk together 2 cups confectioners’ sugar, 1/3 cup lemon juice, and 1 tablespoon lemon zest until smooth. If the glaze is too thick, add more lemon juice a little at a time until pourable; if it becomes too thin, add more confectioners’ sugar a little at a time until you reach the desired consistency.
• Pour the glaze evenly over the cake (the cake can be glazed while still slightly warm). Smooth the glaze lightly if needed. Allow the glaze to set and the cake to cool in the pan for at least 1 hour (or cover loosely with foil and chill overnight) before slicing and serving.
• Store leftovers in an airtight container at room temperature for up to 5 days, or freeze for up to 4 months.