What is the best way to stabilize whipped cream for frosting a cake?

Whipped cream tends to water out slightly after beating so to keep this from happening I use a small amount cornstarch which does not affect the texture.It will not hold up well at room temperature but in the refrigerator will stay well on the cake for 24 hours! Many people have reported that this recipes has saved their lives! For 1 cup of heavy whipping cream, use 2 tablespoons of powdered sugar and 1 teaspoon of cornstarch (if your cream is very low in butterfat use 1 1/2 teaspoons), and 1/2 teaspoon pure vanilla extract. Refrigerate the mixing bowl and (preferably whisk) beater for at least 15 minutes. In a small saucepan place the powdered sugar and cornstarch and gradually stir in 1/4 cup of the cream. Bring to a boil, stirring constantly, and simmer for just a few seconds (until the liquid is thickened). Scrape into a small bowl and cool completely to room temperature. Stir in the vanilla. Beat the remaining 3/4 cup cream just until traces of beater marks begin to show distinctly. Add the cornstarch mixture in a steady stream, beating constantly. Beat just until stiff peaks form when the beater is raised.