Preheat Air Fryer to 400 degrees.
Core and chop apples into bite-sized pieces on a cutting board.
Add the apples to an oven-safe dish that fits in your air fryer. ( I used a 5-inch Ramekin.)
Create a slurry by whisking together the cornstarch, lemon juice, and vanilla extract in a small bowl.
Pour the slurry over the apples and add the cinnamon, brown sugar, and salt. Stir together until the apples are evenly coated.
In a medium shallow bowl add all the topping ingredients.
Using a fork or pastry blender combine all the ingredients (it’s ok if there are still little chunks of butter, just be sure all the flour is incorporated.)
Pour the mixture over the apples and pat down to form a secure crust so the topping doesn’t fly all around the air fryer.
Bake for 15 minutes at 370 degrees or until the crust is golden brown and the apples are softened.
Serve warm with Ice cream or whipped cream!