Preheat Air Fryer at 370°F (188°C). Set at 15 minutes.
In a small bowl, dissolve the cornstarch in water. Set aside.
In a medium bowl, add the apples, butter, brown sugar, cinnamon, and nutmeg. Mix well then drizzle lemon juice and vanilla. Stir in the prepared cornstarch slurry, then sprinkle with salt and continue mixing. Then transfer to a ramekin.
In a small bowl, combine oats, flour, and brown sugar then mix well. Toss in cold butter and push with the back of a fork until combined. Cover on top of the apple filling.
Gently transfer the ramekin onto the Air Fryer tray and slowly insert the tray into the middle cooking chamber near the rotisserie catch.
Air Fry for 12 to 15 minutes until the top is crisp and golden brown in color.
Gently remove the tray from the Air Fryer and allow it to cool before serving.
Serve with a scoop of creamy vanilla ice cream and drizzle with caramel syrup.
Notes
This Air Fryer recipe uses an Instant Vortex Plus Air Fryer Oven. Not all Air Fryers cook the same way. It’s best to keep watch during your initial tests after purchasing.I used Gala apples but Fuji, Honeycrisp, and Granny Smith are delicious choices too.Two small apples can be used instead of 1 medium apple. The apple filling is tender once it reaches 12 minutes but to get an even browning on top, it’s best to add a few more minutes. Keep an eye on the last 3 minutes in the Air Fryer to avoid over browning the topping.If you have a sweet tooth and prefer a sweeter version, add 1 teaspoon or 2 of brown sugar into the filling. But the sweetness in this recipe is perfect for those who wish to avoid overly sweet desserts.