Preheat the oven to 350°F. Line a 9x13 baking dish with parchment paper or spray with non-stick spray.
Make the cake: Whisk together the flour, baking powder, baking soda, and 1 and ½ teaspoons cinnamon in a medium mixing bowl. Set aside. In a large mixing bowl, whisk together the sugars, eggs, yogurt, and vanilla. While whisking, slowly add in the coconut oil. Add the dry ingredients into the wet ingredients and fold together — the batter will be thick. Do not overmix. Spread the batter into the prepared baking dish. Set aside.
For the apples: In a small bowl, add the chopped apples. Add the lemon juice and the remaining cinnamon. Stir together and set aside.
Make the crumb topping: Using a fork, mix together the flour, brown sugar, and cinnamon in a small bowl. Stir in the coconut oil until crumbs form — make sure the coconut oil is slightly cooled so it doesn't melt the ingredients.
Assemble the cake: Sprinkle the apples evenly on the top of the batter. Then, sprinkle on the crumb topping. Press the apple and crumb topping into the cake so it sticks to the batter.
Bake for 50-55 minutes. Baking times may vary, so keep an eye on it. The cake is done when a toothpick inserted into the center comes out clean or with a few moist crumbs. Remove the cake from the oven and allow to cool for 5-10 minutes.
Make the icing: While the cake cools, whisk together the powered sugar, vanilla and almond milk. If to thick, add a little more almond milk. Drizzle as much or as little on the cake. Slice & serve!