30min · 4 servings 1 cup all-purpose flour spooned into measuring cup and leveled-off 1 tsp baking powder 1/4 tsp salt 1/2 cup unsalted butter at room temperature 2/3 cup granulated sugar plus more for sprinkling over cake 2 large eggs 1 tsp vanilla extract 2 apples peeled, cored and cut into 1/2-inch cubes Confectioners’ sugar optional, for decorating cake