Preheat oven to 350℉ and line an 8x8 pan with parchment paper and set aside.
In a bowl using a hand mixer or in a stand mixer, whip the butter and sugars until fluffy. Add in the eggs, sour cream and spices. Whip again until combined.
Mix in the baking soda, baking powder, and gluten-free flour until well combined. Fold in the apples.
Spread half of this batter into the prepared pan. Mix together the cinnamon swirl ingredients and sprinkle this evenly over the first half of the batter. Top with the remaining batter.
In a bowl and using your hands, roughly combine the topping ingredients until you have a crumble. Crumble this over top of the batter. Bake for about 35 minutes or until a toothpick comes out clean. Let cool before slicing and enjoying!
