First, mix together the first 3 ingredients to make pancake batter. Mix in the cinnamon, brown sugar and vanilla extract to the batter. Pour half of the mixture in a greased 9 X 13 baking dish. Then pour the apples over, then pour most of the remaining mixture over the top. I had a bit of the mixture left. If you don't want to waste, just make a couple of tasty pancakes to snack on. :)
In a small bowl, mix together the flour, sugar, baking powder, salt and the beaten egg. This mixture should get very crumbly. Spread these crumbs over the top of the dessert.