Preheat oven to 350 degrees and grease a 9x13 inch sheet pan. In a medium bowl, whisk together all of your dry ingredients for the cake. Set aside.
In the bowl of a stand mixer combine the sugar, oil, vanilla, and strained pumpkin puree. Beat in the eggs one at a time, mixing after each addition.
Add the flour mixture a little at a time to the wet ingredients. Spread batter evenly onto the prepared pan. Bake for 30-35 minutes, until a toothpick comes out clean.
Allow the cake to cool for 1 hour. Meanwhile, in a mixing bowl, whisk together the three milks and Amaretto. Poke holes all over the surface layer of the cake with a fork (I did it about 80 times). Pour it very slowly over the cake, allowing it to seep in. Cover and refrigerate the cake overnight.
Once you are ready to serve, prepare whipped cream by beating the cream until it begins to thicken. Add the powdered sugar, cinnamon and amaretto. Continue to beat until peaks form. Spread evenly over the cake until it looks pretty. Then sift cinnamon over the top of the cake and serve.
Finally, prepare the spiced cream. Beat the cream, sugar, cinnamon, and vanilla in an electric mixer fitted with the whisk attachment until peaks form. Spread evenly over the cake, slice, and serve.