Preheat oven to 350°F (177°C). Lightly grease a 9×13-inch baking pan (or any 3–4-quart baking dish works).

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.

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 OK. Pour and spread the batter over the apples. Sprinkle cinnamon-sugar evenly over the top. Use a butter knife to gently swirl the topping as best you can (the apples get in the way a bit, and that’s fine).

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 you find the top of the cobbler is browning too quickly in the oven, loosely cover it with aluminum foil (I usually do this about halfway through baking). 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.

Cover leftovers tightly and store in the refrigerator for up to 5 days. Reheat in the microwave or bake, covered, in a 300°F (149°C) oven, for 20 minutes or until heated through.