Add all the dry ingredients (rice flour, sugar, bitter cocoa, baking powder and vanilla) in a bowl and mix.
Put the rice milk and the oil in a measuring jug and mix, add the liquid mixture to the dry mixture and whisk.
Wash and dry the apple, peel and dice it, if you prefer, you can cut slices to decorate the surface of the muffins.
Pour the mixture into 4 paper cups, bake in the air fryer at 150 ° C for 20-25 minutes, the apples make the dough more moist, always check the baking by doing the toothpick test: insert the toothpick in a muffin, if it comes out clean, the muffins are cooked.