01 -
Preheat oven to 350°F (177°C). Lightly grease a 9×13-inch baking pan or any 3–4-quart baking dish.
02 -
Melt 2 Tablespoons of butter in a medium saucepan over medium heat. Add the apple slices, brown sugar, lemon juice, flour, and spices. Cook, stirring, for 5 minutes, or until the apples are coated and begin to soften. Transfer apple filling to the prepared baking pan.
03 -
Whisk the melted butter and sugar together in a medium bowl. Add the buttermilk, vanilla, flour, baking powder, and salt, and whisk until combined and mostly smooth. Some small lumps are acceptable.
04 -
Pour and spread the batter over the apples. Sprinkle cinnamon-sugar mixture evenly over the top. Use a butter knife to gently swirl the topping (the apples may interfere slightly, which is fine).
05 -
Bake on the center rack for 48-55 minutes or until the topping is golden and the apple filling is bubbling around the edges. If the top browns too quickly, loosely cover with aluminum foil halfway through baking.
06 -
Remove from the oven, place on a cooling rack, and allow to cool for at least 5 minutes before serving. Serve warm, room temperature, or cold; on its own or topped with vanilla ice cream and/or salted caramel sauce.