Mix all the ingredients for the milk crumble filling until well combined
Cut the apple in half, then into quarters. Remove the seeds and slice into thin pieces about 0.25 cm thick.
Take 1 puff pastry sheet, spray water on it, then evenly sprinkle sugar over the surface. Cover with another puff pastry sheet and press firmly.
Cut the puff pastry from step 3 in half. Pipe an appropriate amount of milk crumble filling onto it, then layer the apple slices from step 2 on top.
Placethe ingredients in the air fryer basket. Select [Air Fry] mode,set to 15 minutes at 200°C, and start cooking
Move the air fryer basket to the first rack position. Select [Air Fry] mode, set to 5 minutes at 200°C, and cook until the puff pastry is golden brown, and ready to serve.