Preheat oven to 350 degrees and generously grease a 9-inch springform pan.
Whisk together flour, pudding mix, sugar, baking powder, and salt in a medium bowl. Set aside.
In a mixing bowl, add eggs, ricotta, butter, pumpkin puree, and vanilla. Mix until smooth.
Gradually add in the dry ingredients and mix just until blended. Mix in the pumpkin spice.
Spoon the cake batter into the prepared pan and spread it evenly.
Bake for 50-60 minutes, or until golden brown and cake is set in the middle.
Allow the cake the cool. Then, remove it from the springform pan.
Once completely cool, sprinkle powdered sugar on top and serve.