Prehea thet oven to 350 °F/170°C.
Grease a square baking dish with some coconut oil.
With an electric mixer, mix the coconut oil with the coconut sugar, pumpkin cubes, and eggs until you get a smooth consistency.
In a separate bowl, mix together the oat flour with the protein powder, baking powder, salt, and the spices.
Add the dry ingredients to the wet ones and mix until well combined. Pour into the baking dish.
For the topping, mix all ingredients together. Crumble on top of the cake mixture and bake in the oven for 45 minutes or until a stick comes out clean.
Serve warm with some maple syrup (optional).