Preheat the oven to 350°F (175°C) and grease a cake pan.
In a bowl, mix flour, baking powder, baking soda, cinnamon, nutmeg, ginger, and salt.
In another bowl, combine pumpkin, mashed banana, sugar, oil, vanilla, and almond milk.
Gradually add the dry mixture to the wet ingredients and stir until just combined.
Pour the batter into the prepared pan.
In a separate bowl, mix sugar and cinnamon for the streusel. Sprinkle over the batter.
Bake for 45-50 minutes, or until a toothpick comes out clean.
Let the cake cool before serving.