Preheat the oven to 350?F (177?C). Grease a 9-inch square or springform baking pan with nonstick spray.

In a medium bowl, whisk together the crumb topping ingredients: flour, brown sugar, and cinnamon. Cut in the cold butter until you get clumps and crumbs. Set aside.

In a large bowl, whisk together the dry ingredients for the cake: flour, baking soda, baking powder, salt, cinnamon, nutmeg, cloves, and ginger.

In a medium bowl, whisk together the wet ingredients: pumpkin, brown sugar, oil, maple syrup, and milk. Pour the wet ingredients into the dry ingredients and stir until just combined. The batter will be very thick.

Spoon the batter into the prepared pan and spread it evenly. Pour the crumb topping over the batter and gently press it down.

Bake for 30-35 minutes. Check for doneness at the 30-minute mark by inserting a toothpick in the center. If it comes out with wet batter, bake for another 5 minutes.

For the icing, whisk together the icing ingredients, adding extra creamer or milk if necessary to achieve desired consistency. Drizzle over the cake once it's warm or cooled.

Cover any leftover cake tightly and store at room temperature or in the refrigerator for up to 3 days.