Preheat your oven to 350 degrees and prepare a 9 inch square or 7"x11" deep baking dish by greasing and lining with parchment paper
In a large bowl, whisk together 2 cups of all purpose flour, 1 teaspoon of baking soda, 1/2 teaspoon of baking powder, 1/2 teaspoon of salt, 1 teaspoon of ground cinnamon and 1-2 teaspoons of pumpkin spice or chai spice (depending on how bold you want your flavors) and set aside
In a separate bowl, whisk together 1 1/4 cup of pure pumpkin puree with 1/3 cup of tightly packed brown sugar, 1/2 cup of canola oil, 1/4 cup of maple syrup and 1/4 cup of whole milk until it is smooth and fully combined
Add the pumpkin mixture into the dry ingredients and stir until just combined
Make the crumb topping by cutting 4 tablespoons of cold, cubed butter into a combination of 1/3 cup of finely chopped pecans, 1/3 cup of all purpose flour, 1/2 cup of tightly packed brown sugar, a teaspoon of ground cinnamon, 1/4 teaspoon of nutmeg and 1/4 teaspoon of salt until the texture is like damp sand
Pour the thick pumpkin batter into the prepared baking dish and then top with the pumpkin spice crumble topping (or layer the ingredients, see instructions above)
Bake uncovered in a 350 degree oven for 30-35 minutes Note: Do not remove the cake from the oven until the center feels set and a toothpick comes out mostly dry from the very center of the cake Transfer the coffee cake onto a cooling rack and let it cool still in the baking dish for about 10 minutes before transferring it directly onto the cooling rack to continue cooling
Make the vanilla drizzle by combining 3/4 cup of confectioners sugar with 1/2 teaspoon of vanilla extract in a small bowl and adding just enough whole milk or heavy cream to create a drizzle-able consistency (1-2 tablespoons)
Slice the cooled coffee cake, drizzle with the spiced vanilla drizzle and dust with confectioners sugar
Serve warm or at room temperature