Preheat the oven to 350°F (175°C). Spray a 9x9-inch baking pan with nonstick cooking spray.

In a large bowl, mix 2 cups flour, granulated sugar, baking powder, salt, and pumpkin pie spice. Whisk to combine.

Stir in the pumpkin puree, vegetable oil, vanilla, and nonfat milk until well mixed. Pour the batter into the prepared pan and set aside.

In a small bowl, mix melted butter with 1/4 cup flour, brown sugar, cinnamon, and a pinch of salt. Stir with a fork to combine.

Spread the brown sugar mixture on top of the pumpkin cake batter.

Bake for 30-40 minutes or until a toothpick inserted 2 inches from the side of the pan comes out clean.

Store covered on the counter for up to 2 days or freeze for up to one month.