4tablespoonsbuttersoftened to room temperature (1/2 stick of butter)
In a medium bowl, toss the apples with the lemon juice and vanilla. Place the apples into a cake barrel accessory pan, spreading evenly to the edges. The apples can overlap.
In a medium bowl stir together the flour, oats, brown sugar and cinnamon. Using a pastry blender, two forks or a whisk, mix the butter into dry ingredients until lumpy and coarsely mixed. Most of the dry ingredients should be incorporated with the butter to form large crumbs.
Sprinkle the mixture evenly over the apples.
Cover with foil and bake in an air fryer at 340°F/170°C for 20 minutes.
Remove foil and bake for another 8 minutes to create a crispy top layer.
I used 2 Granny Smith and 2 Honeycrisp. Firm, tart and sweet apples work the best for apple crisp. Feel free to experiment with different varieties.The apples remain somewhat firm in the air fryer, yet soft enough to enjoy. So if you like a slightly softer apple base, then cook for an additional 5 minutes prior to removing the foil.