Directions

1. In a small bowl, combine 2/3 cup flour, 1/2 cup brown sugar, 1 teaspoon cinnamon and 1/8 teaspoon salt. Add in 6 tablespoons cold butter cut into cubes. Using a pastry blender, cut butter into the dry ingredients until the mixture looks like coarse crumbs. Set aside.
   
2. Preheat oven to 350°. Grease a 9-inch cake pan with cooking spray. Set aside.
   
3. In a medium bowl, whisk together 1 1/2 cups flour, baking powder, baking soda, 2 teaspoons cinnamon, ginger, nutmeg, allspice and 1/2 teaspoon salt.
   
4. In the bowl of a stand mixer with paddle attachment, add 1/2 cup softened butter and 1 cup brown sugar and beat on medium-high speed until well combined. Beat in the eggs, one at a time, scraping down the sides of the bowl with a rubber spatula.
   
5. Add in 1 teaspoon vanilla extract. Add the pumpkin puree and Greek yogurt and mix until just combined. Slowly add in the flour mixture. The batter will be thick. Spread half of the batter in the prepared pan. Sprinkle half of the streusel over the batter. Spread the remaining batter over the streusel and top with the remaining streusel.
   
6. Bake until a toothpick inserted into the center of the cake comes out clean, about 45 minutes. Transfer the pan to a wire cooling rack and let cool for about 15 minutes. Remove the cake from the pan and slide the cake onto the rack.
   
7. In a small bowl, whisk together powdered sugar, 1/8 teaspoon cinnamon, milk and 1 teaspoon vanilla. Drizzle over the top of the cake. Cut into wedges and serve.