1. Using a cake pan that is 8-9 inches in diameter, spray the sides and bottom of the pan with canola oil spray. You can add a piece of parchment paper on the bottom to help with removing the cake later.
2. Preheat the oven to 350'F. Cut, remove skin and core 2 apples into small pieces (approximately 1.5-2 in by 1/4 in thick.) Core, remove skin, and thinly slice the other two apples for the top of the cake.
3. Add the almond milk, sugar, and oil to a mixing bowl and whisk together.
4. Add the dry ingredients - flour, baking powder, cinnamon - to another bowl and mix together.
5. Add the dry ingredients to the almond milk mixture, and mix with a hand mixer to combine. The mixture will be somewhat thick.
6. Add the smaller apple pieces into the batter and stir with a rubber spatula to combine.
7. Pour into the cake pan and spread it out evenly.
8. Cover the top of the cake with the thinly sliced apples, into a circular pattern around the cake - starting at the edges is easiest. Do this in an overlapping fashion until all of the top of the cake is covered. Sprinkle with 2 TBSP of sugar on top.
9. Bake the cake for 50 - 60 minutes until cooked through. Test using a toothpick in the center to see if it comes out clean. Take out of the oven to cool.