Make the streusel: In a medium bowl, combine brown sugar, flour, pumpkin spice, and salt. Cut in the cold butter with a pastry cutter or your fingers until crumbly. Refrigerate while you prepare the cake.

Prepare the cake batter: Heat oven to 350°F (175°C). Spray an 9×9 square or 9-inch round or large loaf pan with nonstick spray. In a large bowl, whisk together the brown and white sugar and eggs until smooth.

Add pumpkin purée, melted butter, sour cream, pumpkin spice, vanilla, and salt. Mix well.

Add baking powder, baking soda, and flour until just combined (do not over mix).

Assemble: Spread half of the batter into the prepared pan. Sprinkle with half of the streusel. Add the remaining batter and top with the rest of the streusel. **The batter will come up very high and bake to the top. This is correct. The glaze is added after the pumpkin cake is removed.

Bake for 45-60 minutes (Depending on the size of your pan. My 8x8 and loaf pan both take 50-60 minutes in my oven) until a toothpick inserted into the center comes out with a few crumbs. Allow to cool for ten minutes before removing.

Glaze (optional): In a small bowl, whisk together confectioners’ sugar, pumpkin spice, salt, and just enough milk to reach drizzling consistency. Drizzle over cooled cake.