Preheat the oven to 350F.
Place the stick of butter in a 9x9-inch square baking dish and place it in the oven to melt for 3-4 minutes until fully melted. Remove from the oven and set aside.
In a medium mixing bowl, whisk together the flour, baking powder, and salt. Add the sugar and whisk to combine.
Pour in the buttermilk, vanilla extract, and lemon extract and whisk just until combined.
Pour the batter evenly over the melted butter in the pan (do not stir).
Spoon the lemon pie filling over the batter.
Bake at 350F for 45-55 minutes until the edges of the cobbler are golden brown.
Cool slightly before serving.