Stabilizing whipped cream means adding something to it that helps keep it stiff enough to hold its shape and not melt or lose its decorative structure. This is especially useful when you need to pipe whipped cream around a pie or decorate a cupcake or any other time you need it to look pretty. You can stabilize your whipped cream by adding cornstarch, more confectioner's sugar (which contains cornstarch), milk powder, or pudding mix and beating until stiff peaks form.