Peel, core and dice the apples into small pieces.
Chop the nuts as necessary
In a large mixing bowl, measure all the dry ingredients and stir well to combine.
In a separate bowl, beat the egg with the oil and vanilla.
Make a well in the dry ingredients and add the wet mix. Add the apples and nuts on top. Stir to combine.
The dough should be crumbly and damp; more like streusel than cake batter. If too dry, add a teaspoon of water at a time until the dough is evenly moist.
Prepare the baking dish with cooking spray and set the Ninja Foodi to Air Bake for 35 minutes at 350°F/180°C.
When the oven is preheated slide in the baking dish and bake, turning the dish about halfway through. The cake is done when the top of the snack cake is golden brown, the edges of the cake will have pulled away from the sides, and a toothpick inserted into the center come out clean.