Grease a 9×13-inch baking pan.
In a medium saucepan, melt the butter over medium heat.
2 tablespoons butter
Add apples, brown sugar, lemon juice, and spices. Stir and cook for 5 minutes, or until the apples soften.
4 apples, ¼ cup brown sugar, 1 lemon, 1 teaspoon cinnamon powder, ½ teaspoon nutmeg, ¼ teaspoon cloves
Transfer the apples to the greased baking pan.
In a bowl, whisk together melted butter and sugar.
¼ cup unsalted butter, ½ cup granulated sugar
Add buttermilk, vanilla, flour, baking powder, and salt, whisking until smooth (small lumps are fine). Add the milk gradually, it should be a bit runny.
½ cup buttermilk, 1 tablespoon vanilla extract, 1 ½ cup all-purpose flour, 1 teaspoon baking powder, ¼ teaspoon salt, ¼ cup milk
Pour the topping over the apples in big chunks. Sprinkle cinnamon or vanilla sugar on top and swirl gently with a butter knife - try to expose some of the apples, this will yield different textures.
2 tablespoons cinnamon or vanilla sugar
Place in the air fryer and bake at 160ºC (320°F) for 50 minutes, until the top is golden and apples bubble at the edges. Cover with foil halfway if browning too quickly.
Serve warm with ice cream.
Ice cream