Measure out all the cake ingredients ahead of time so you can prepare the cake quickly. If the batter sits too long it will be difficult to mix and the cake will deflate in the oven.
Preheat the oven to 350 degrees, Fahrenheit.
Grate the apples, then sprinkle the grated apple with two tablespoons of flour to coat.
Line the bottom of a 9x13 casserole dish with a piece of parchment paper.
In a large mixing bowl, mix together the sticky glaze ingredients.
Pour the glaze mixture into the bottom of the parchment lined casserole dish and spread evenly until the entire bottom of the dish is covered.
In the same mixing bowl used to make the glaze, prepare the flax egg by whisking together 1 tablespoon of ground flaxseed with 2 1/2 tablespoons of water. Allow to sit for 5-10 minutes, or until gelatinous in texture. Then, add in the light brown sugar, melted vegan butter, room temperature vegan yogurt, and vanilla extract. Whisk ingredients together until combined.
Sift in the baking soda and flour and fold gently into wet ingredients. Avoid fast movements or the cake batter will get tough and stringy.
Lastly fold in the grated apple until just combined. The batter will be thicker and not runny.
Spread the cake batter over top the glaze in the casserole dish and gently spread it until fully covering the glaze. The best, easiest way to do this is to use a 3 tablespoon cookie scoop and place scoops of cake batter about 2 inches apart over top the glaze, similar to how you would scoop cookie batter onto a baking sheet. Then, gently spread the cake batter smooth using a silicone spatula. This will help prevent the glaze from moving.
Bake for 40-45 minutes or until a toothpick comes out clean.
Remove from oven and allow to cool in pan for 5-10 minutes.
Once cooled slightly, slide a knife around the edges of the cake to ensure no sticking, then put a cookie sheet over top the casserole dish. Using oven mitts, carefully invert the cake so the sticky glaze will be on top.
Peel off the parchment paper from the glaze and slice the cake. Enjoy plain or with coconut whip or vanilla ice cream.
Store leftovers at room temperature for 2-3 days. Because this cake is made with fresh apples, it will not last long.
How to easily spread the cake batter overtop the glaze: I like to do this by using a cookie scoop and placing scoops of batter overtop the glaze and then lightly spreading together with a baking spatula.
Use enough parchment paper. If you use too little parchment paper, the glaze is likely to seep underneath it and therefore not stick to your cake at all. Using enough to also slightly cover the sides of the casserole dish will prevent this.
Over mixing or whisking this batter together quickly will leave you with a very dense, very gummy cake.
Using room temperature vegan yogurt will result in a lighter, fluffier cake batter.