Preheat the oven to 350 degrees.  Spray an 8 x 8 pan with cooking spray and set aside.

In a small bowl combine all ingredients for the streusel and mix until crumbly.

In a large bowl combine the flour, baking powder, salt, cinnamon, and ginger.  Mix and set aside.

In a medium bowl cream together the brown sugar, granulated sugar, and butter until smooth.  Add in the eggs and mix well.

Stir in the pumpkin puree, sour cream, and vanilla paste and mix until well combined.

Add the wet ingredients to the dry ingredients and stir until just combined.

Pour half the batter into the prepared pan and smooth the top with a spoon..  Sprinkle with half of the steusel. 

Gently spread the remaining batter over top of the streusel.  Sprinkle with remaining streusel.

Bake for 35 minutes or until a toothpick inserted into the center comes out clean.