Preheat the oven to 350°F (175°C) and grease a cake pan.
In a bowl, combine flour, baking powder, baking soda, cinnamon, nutmeg, and salt.
In another bowl, whisk together brown sugar, oil, pumpkin puree, almond milk, and vanilla.
Slowly fold in dry ingredients until smooth.
Stir in chocolate chips.
For the streusel, mix sugar, flour, cinnamon, and vegan butter. Crumble over the batter.
Bake for 35-40 minutes or until a toothpick comes out clean.
Let the cake cool for 10 minutes, then transfer to a wire rack to cool completely.