Preheat oven to 350°F (175°C). Grease a cake pan.
Whisk together flour, baking powder, baking soda, cinnamon, nutmeg, and salt.
In another bowl, mix brown sugar, oil, pumpkin puree, almond milk, and vanilla.
Gradually add dry ingredients to the wet mix, stirring until smooth.
Combine streusel ingredients in a bowl. Mix until crumbly.
Pour batter into the pan and sprinkle streusel on top.
Bake for 35-40 minutes or until a toothpick comes out clean.
Cool for 10 minutes before transferring to a rack.