In a medium bowl, mix the brown sugar and sugar together.
To the sugar mixture add the cinnamon and flour and stir to combine.
Cut the margarine or butter into small squares then add to the brown sugar and flour mixture.
Set aside in the refrigerator until ready for it.
In a large bowl, add the dry ingredients and mix with a whisk to incorporate it well.
Add the diced apples to the dry ingredients and toss to coat the apples.
Make a well in the dry ingredients and add wet ingredients.
Using a wooden spoon or spatula mix until all the dry ingredients are moistened. But don’t over mix or the cake could be tough.
Spoon the batter into a greased 9-inch pan.
Sprinkle the crumble topping on top of the batter.
Bake 400 degrees until toothpick comes out clean when checked in the center and the cake is golden. Mine cooked in 40 minutes.