Preheat oven to 350 degrees. Grease a 9 x 9 baking pan with nonstick cooking spray.
In a large bowl, whisk together the sugar, butter, pumpkin, and eggs using a handheld mixer. Add in the flour, baking powder, salt, and spices. Stir to combine. Pour half of the batter into the bottom of the greased baking pan using a rubber spatula to smooth.
In a small bowl, toss together the brown sugar and cinnamon for the filling. Sprinkle the filling over the batter in the pan.
Top with the remaining batter, using a spatula to spread.
In the small bowl, combine the brown sugar, oats, and butter for the streusel. Use hands to sprinkle the streusel over the top of the coffee cake.
Bake for 40-45 minutes until a toothpick inserted in the middle comes out clean. Cool for 5 minutes on a wire rack before serving.
Store coffee cake in an airtight container in the fridge for up to a week. You can easily make this recipe ahead of time and freeze as well.