In a large bowl, stir the dry ingredients together: Flour, brown sugar, baking powder, baking soda, and spices.
In a separate small bowl, combine the wet ingredients: pumpkin puree, maple syrup, sour cream, eggs, and coconut oil.
Add the wet ingredients to the dry ingredients. Gently fold until fully combined.
Pour half of the cake batter into the pan. Sprinkle half the streusel crumble over the batter. Spread the remaining batter over the streusel crumble. Top with the remaining streusel.
Bake for 35-40 minutes until a toothpick inserted in the center comes out clean. (Recommend starting on the low side and checking it)