Preheat the oven to 350℉. Spray a 9x13 cake pan with nonstick cooking spray. Set aside.
In a small mixing bowl, whisk together the all-purpose flour, pumpkin pie spice, baking powder, baking soda, and salt.
1¼ cup all-purpose flour, 2 teaspoons pumpkin pie spice, 1½ teaspoons baking powder, ½ teaspoon baking soda, ½ teaspoon salt
In a separate larger mixing bowl, whisk together the eggs, granulated sugar, and light brown sugar until smooth and thickened.
4 large eggs, 3/4 cup granulated sugar, 1/2 cup packed light brown sugar
Add in the pumpkin puree and vanilla extract, and continue mixing until all the ingredients are fully incorporated.
1 cup canned pumpkin puree, 2 teaspoons vanilla extract
Slowly add the dry ingredients into the larger bowl of wet ingredients. Use a silicone or rubber spatula to gently fold everything together until you no longer see flour streaks in the pumpkin batter. Don't overmix.
Pour the pumpkin cake batter into the prepared pan and smooth the top. Bake for 25-30 minutes or until a toothpick inserted into the center comes out clean. Remove the cake from the oven and allow the cake to cool completely.
Once the cake has cooled completely to room temperature, use a fork to poke holes all over the top of the cake.
In a mixing bowl, whisk together the sweetened condensed milk, evaporated milk, half and half, and cinnamon. Slowly pour the milk mixture evenly over the cake, giving it time to soak in between each pour. Cover the cake pan with a lid, or plastic wrap, and refrigerate for at least 6 hours or even better for overnight.
1 can (14 oz) sweetened condensed milk, 1 can (12 oz) evaporated milk, 1/4 cup half and half, ½ teaspoon ground cinnamon
Right before serving make the whipped cream topping. Into a large mixing bowl using a handheld blender, or use a stand mixer with the whisk attachment, beat the heavy whipping cream, powdered sugar, and vanilla extract until stiff peaks form. Start at low speed and increase the speed as needed.
2 cups heavy whipping cream, 1/2 cup powdered sugar, 1 teaspoon vanilla extract
Evenly spread the whipped cream over the chilled cake and dust with a light sprinkle of pumpkin pie spice (optional).
pumpkin pie spice
Slice into squares and serve the cake chilled. Enjoy!