Directions:
Preheat and Prepare: Preheat your oven to 350°F. Lightly grease a 9×13-inch baking pan with nonstick spray and set aside.
Mix Ingredients: In a large bowl, combine the spice cake mix and vanilla pudding mix. Add the melted butter, milk, heavy cream, and pumpkin. Stir until the mixture is well combined.
Bake: Spread the batter evenly in the prepared pan. Bake in the preheated oven for about 35 minutes, or until a toothpick inserted into the center comes out clean.
Cool and Serve: Allow the cake to cool in the pan for 10 minutes before cutting into squares. Serve warm or at room temperature.