Preheat your oven to 180 C.
Grease the bottom and sides of a baking dish, 11x7 will work perfect. Place the cashews in the bottom of the baking dish, spread into an even layer and sprinkle two tablespoons of brown sugar on top. Place the dish in the oven and let them bake for 10 minutes.
While the cashews are toasting, take a medium-sized bowl and quickly blend the eggs, butter, sugar, flour, baking powder, vanilla extract, cinnamon, and nutmeg. Peel and cut your apples into slices and set aside.
Remove the cashews from the oven and place the sliced apples over the top, trying your best to create an even layer of apple slices. Sprinkle the two leftover tablespoons of brown sugar over the apples and pour the batter over the top. Place into the oven for 35 minutes, or until the cake is springy to the touch.
Let cool for 30 minutes then use a butter knife to loosen the edges of the cake then carefully flip the cake over on to a large plate (lay a large plate upside down on the baking dish, hold onto both and flip over setting the plate on the counter, then gently lift the baking dish up). Serve with ice cream or whipped cream.