Preheat the oven to 350°F. Spray a 9x13-inch cake pan with cooking spray. Line the pan with parchment paper.
Combine the flour, baking powder, baking soda, cinnamon, ginger, nutmeg, cloves, and salt in a bowl, whisking to combine.
In a separate large bowl whisk the brown sugar, oil, pumpkin, sour cream, milk, and vanilla until smooth. Whisk in the eggs, one at a time, beating well after each addition.
Create a well in the center of the dry ingredients. Pour the wet ingredients into the dry ingredients and stir with a wooden spoon or wooden spatula to combine.
Pour the batter into your prepared cake pan. Smooth the batter out into an even layer so it takes up the whole pan, if necessary. Crumble your streusel over top of the batter in an even layer.
Bake the entire cake for 45 to 50 minutes or until a toothpick inserted into the center of the cake comes out clean. Let it cool completely in the pan before drizzling with the maple glaze.