Preheat oven to 350°F (175°C). Grease your cake pan.
In a bowl, whisk together flour, baking powder, baking soda, cinnamon, nutmeg, and salt.
In another bowl, beat sugar and butter until fluffy.
Add eggs, pumpkin, and vanilla to the butter mixture. Mix well.
Gradually add dry ingredients to wet ingredients. Stir until smooth.
For the streusel: combine sugar, flour, and cinnamon. Add butter to make crumbs.
Pour batter into the pan. Sprinkle streusel on top.
Bake for 35-40 minutes or until a toothpick comes out clean.
Cool for 10 minutes, then transfer to a cooling rack.