Peel, core and roughly chop the apples, and tip them into a bowl. Add ½ tsp mixed spice and 1 tbsp of the sugar and stir to mix.
Spoon the spiced apple pieces into 3 small ovenproof dishes and cover in foil.
Select Air Fry and set the temperature to 188°C and the time to 15 minutes and press start.
Ignore when prompted to add food, as the dishes will already be in the air fryer.
While the apples are cooking, make the crumble. Sift the flour in a bowl, add the butter, sugar and 1 tsp mixed spice and a small pinch of salt, and use your fingertips to it all together to form clumps and make a chunky, sandy mixture.
When the frying program finishes, stir the chocolate and marshmallows into the now softened apples, and spoon the crumble mixture over the apples to cover them.
Put the dishes back into the fryer, uncovered and select Bake, setting the temperature to 188°C and time to 7 minutes, until the crumble is golden and crisp on top.
Enjoy warm, served with double cream or custard.