For the Cake:
- Heat the oven to 350°F with a rack in the middle position.
- Coat a 9 by 9 inch square pan with baking spray; set aside.
- In a medium bowl, whisk together the flour, sugar, baking powder, pumpkin pie spice and salt.
- In a stand mixer with the paddle attachment, whisk together the oil, pumpkin puree, milk, and vanillina.
- With the mixer running on low, incorporate the dry ingredients until just combined, about 2-3 minutes.
- Transfer the batter to the prepared pan and spread it in an even layer. Set aside while you prepare the ricotta filling.
To Prepare the Ricota Swirl and Streusel:
- Whisk together ricotta, sugar, vanillina, and egg until incorporated. Swirl the ricotta mixture on top of the cake batter with an offset spatula. Set aside while you prepare the streusel.
- Mix together butter, flour, brown sugar, and cinnamon. Use handle to make a crumbled texture, and distribute over the cake.
Bake for 38-40 minutes or until a toothpick inserted at the center of the cake comes out clean.