For the Chocolate Chip Streusel:
1/3 c. flour
1/3 c. rolled oats
1/2 c. firmly packed brown sugar
1 t. cinnamon
pinch of salt
6 T. butter (cold)
1/2 c. semi-sweet chocolate chips
For the batter:
1 1/2 c. flour (I used 1 c. all-purpose, 1/2 c. whole wheat flour)
2 t. baking powder
1/2 t. baking soda
2 t. cinnamon
1/4 t. nutmeg
1/2 t. salt
1 stick (8 T.) unsalted butter (melted)
1 c. firmly packed brown sugar
1/2 c. pumpkin puree (can of pumpkin that says 100% pumpkin)
1/2 c. sour cream
For the glaze:
1/2 c. powdered sugar
1 t. half & half (whole milk/cream work too)
1 t. vanilla extract
Heat the oven to 350°F. Grease and flour a 9-inch cake pan.
For the streusel: Combine the flours, oats, brown sugar, cinnamon, and salt. Cut the butter into small cubes and toss in with the dry ingredients. Set aside.
For the batter: In a medium bowl, whisk together the flour, baking powder, soda, cinnamon, nutmeg, and salt, set aside. In a large bowl, beat the melted butter into the brown sugar with an electric mixer. Beat in one egg at a time. Add in the pumpkin puree and sour cream. Stir in the flour mixture.
Spread half of the batter into the greased pan. Dollop half of the streusel over the batter. Pour the other half of the batter on top of the streusel. Sprinkle the remainder of the streusel on top. Bake until a toothpick comes out clean of the center, roughly 50 minutes. Let cool in pan for 15 minutes. Slide the cake onto a cooling rack.