Preheat oven to 350°F.
Pour melted butter into a 9-inch square pan.
Take a little more softened butter and rub along the sides of dish.
Sprinkle brown sugar evenly over the melted butter. (*See notes for alternative spiced topping)
Peel, core and thinly slice apple.
Layer the apple slices in a circular pattern or just lay them in the bottom, making sure they don't overlap a lot.
Place the pan into the fridge (Don’t skip this step).
In a bowl, cream together the vegan shortening and the vegan sugar.
Add in the milk, vanilla, and applesauce and beat again until combined.
Sift in the flour, baking powder, cinnamon, nutmeg, ginger, allspice, and salt. Beat together, scraping down as needed.
Remove the pan from the fridge. Pour the batter over apples.
Bake cake for 30-35 minutes or until a toothpick inserted comes out clean.
Once done, very carefully remove from the oven and immediately place a heatproof serving plate upside down over cake pan. Flip the plate and pan over at the same time.
Let sit like this for 5 minutes so the caramelized mixture drizzles down over the cake. Very gently remove the pan. Best served warm.
Cake can be stored at room temperature in an air tight dish for up to 3 days.