1. Peel, core and chop the apples coarsely. Add them to a heatproof dish/baking thin that fits in your Air Fryer. Add lemon juice, vanilla extract, brown sugar, and cinnamon and mix well. Set your Air Fryer to a temperature of 180°C (350°F) and bake the apples for about 10 minutes. Stir once and bake for 10 minutes more.

2. While the apples are in the Air Fryer, prepare the streusels. Add the flour, brown sugar, cinnamon, and butter to a small bowl and rub everything between your fingers until you get different-sized streusels. Distribute the streusels evenly on top of the pre-baked apples and continue baking for 8-10 minutes at the same temperature until the streusels are lightly browned. Serve the apple crumble with some whipped cream, custard, or vanilla ice cream.