Preheat oven to 350°F. Grease a 9x9-inch baking pan.
In a large bowl, mix together flour, granulated sugar, brown sugar, baking powder, salt, and pumpkin pie spice.
In another bowl, whisk together pumpkin purée, vegetable oil, eggs, and milk.
Pour the wet ingredients into the dry ingredients and mix until just combined.
In a small bowl, mix the streusel ingredients until crumbly.
Pour half of the batter into the prepared pan. Sprinkle half of the streusel over the batter. Repeat with remaining batter and streusel.
Bake for 35 minutes, or until a toothpick inserted into the center comes out clean.