Mix the flour, both sugars, salt, and spices together.

Use a pastry cutter to cut the butter into the flour mixture and blend. The mixture should resemble large crumbs and stick together when you press them together.

Set aside in the refrigerator until needed.

Preheat the oven to 350°F. Grease and flour a 9 x 9 baking pan. Set aside.

Mix together the flour, baking powder, baking soda, salt, spices, and sugars together in a bowl. Set aside.

Mix together the pumpkin puree, oil, yogurt, and eggs together in a separate bowl until well-combined. Set aside.

Pour the wet ingredients into the dry ingredients and mix until just combined- you want no streaks of flour, but you do want lumps in the batter.

Pour about 2/3 of the batter into the baking pan, then top with 1/2 of the crumble topping. Top that with the remaining batter, followed by the remaining crumble.

Bake for 35 - 40 minutes, or until a toothpick comes out clean.

Allow the cake to cool completely in the pan, then cut and serve. Top with powdered sugar, if desired.