Preheat the oven to 350. In a large-sized mixing bowl, add the All Purpose Flour, Pumpkin Pie Spice, Baking Powder, Baking Soda, and Salt. Whisk until combined.

In a large bowl, combine the Dark Brown Sugar, Granulated Sugar, Greek Yogurt, Pumpkin Puree, and Milk.

Add the wet ingredients to the dry ingredients. Mix but be careful not to over-mix the cake batter as that will make your cake too dry. The batter should be nice and thick.

In a small bowl add 1/2 cup All Purpose Flour, Dark Brown Sugar, Ground Cinnamon, and a pinch of Salt. Cut the cold butter using either a pastry blender/cutter, fork, or your fingers. Be sure to really get in there and mix well. It will create small lumps. I prefer using my hands, even though it is the messiest of the options.

Pour the batter into a prepared 9 x 13 greased/sprayed baking pan. Sprinkle with streusel topping to completely cover the top. Bake the cake for 28-34 minutes. I would check at 28 minutes by inserting a toothpick until it comes out mostly clean. Some ovens bake more hot than others so watch the remaining 5 or so minutes. Set on a rack to cool.

You can either drizzle the icing on a warm or cooled cake. I prefer when the cake is cooled. To make the icing, take a small bowl and whisk the Confectioner’s Sugar (aka Powdered Sugar) with one tablespoon of Milk and 1/4 tsp of Vanilla Extract. Mix well and drizzle over the cake.

Cut into squares and enjoy!