I prefer whipping my own cream over Cool Whip, but I always wondered how to maintain his stiffness - here’s the answer!
1 pint heavy cream, whipped
3 TBS quince jelly, melted
In a chilled mixing bowl, whip heavy cream until stiff. Gently melt quince jelly over a double boiler until smooth. Gently mix sweetener into the whipped cream. Serve immediately.
The jelly has an added benefit over just sugar, it acts as a stiffener and helps whipped cream stay firm for hours. (Another way to improve chances of making perfect whipped cream is to freeze the bowl, cream, and the whisk for 15 minutes).
* NOTE: I have also tried adding just a spoonful of Instant Vanilla Pudding to the whipping cream as I'm whipping it. It adds a good flavor and helps maintain stiffness.