1. Make the pudding by whisking it into 2 cups of cold milk. 2. Next whisk in the can of pumpkin and 2/3 of the container of whipped topping. 3. Stir in pumpkin pie spice. 4. Cover the top of the mousse with a thin layer of whipped topping. This can be served in a bowl, individual cupcake papers or a pie crust.