Cut the apples in half from top to bottom and use a spoon to scoop out the core/seeds and make a shell.
Brush the melted butter over the cut apples. Combine the white sugar and cinnamon and sprinkle over the apples.
Place them in the air fryer basket and cook for 10-12 minutes* (see note).
While the apples are cooking combine the topping ingredients and mix until fully combined.
Open the air fryer and add the topping to the apples, bake an additional 5-6 minutes or until the topping browned and the apples are tender.
Serve with ice cream.
Depending on the size of the apples, you may have extra topping and can use it to bake more apples.*Different varieties of apples will require different cooking times. After the initial cook, gently poke one of the apples with a fork, it should be almost tender. If it isn't cook a few more minutes before adding the topping.Leftovers can be refrigerated for up to 4 days.