Preheat oven to 350℉, and grease an 9” square pan.
Combine all streusel ingredients in a small bowl, mixing with a fork until crumbly.
In another bowl, combine the sugars, vanilla, pumpkin, oil, sour cream and eggs.
In a large bowl stir together the flour, baking powder, baking soda, salt, cinnamon, and pumpkin spice. Make a well in the center and add the wet ingredients, gently folding until just combined.
Spoon the batter into the greased pan and top evenly with streusel. Bake for 45-55 minutes, checking after 40 minutes. Cake is ready when a toothpick inserted into the middle comes out clean. Cool completely before icing
In a small bowl beat the cream cheese with powdered sugar, milk, vanilla and cinnamon until smooth. Drizzle over cake. Cut into squares and enjoy.
Room temperature storage: This cake can be stored in an airtight container on the countertop for up to 4 days. Heat individual slices in the microwave for 15 seconds to rewarm.Freezing: This cake can also be frozen for up to 3 months by wrapping individual slices or the whole cake in 2 layers of plastic wrap. Thaw at room temperature before serving.