01 -
Preheat the oven to 350°F (175°C). Place 1/2 cup of unsalted butter in a 9×9-inch baking dish and let it melt in the oven, about 3-4 minutes.
02 -
Whisk together flour, baking powder, salt, and sugar in a large bowl. Add buttermilk, vanilla extract, and lemon extract (if using). Stir until smooth and thick but pourable.
03 -
Pour the batter evenly over the melted butter in the baking dish. Do not stir.
04 -
Distribute the lemon pie filling or lemon curd evenly over the batter. Allow it to settle naturally.
05 -
Bake in the preheated oven for 45-55 minutes, until edges are golden and a toothpick inserted into the batter comes out with moist crumbs.
06 -
Remove from the oven and let it cool for 10-15 minutes to allow the filling to set.
07 -
Cut into squares and serve warm. Optionally top with whipped cream, ice cream, or powdered sugar.