Before beginning, chill your bowl, beaters and whipping cream well. This produces the best volume and greatest stability. To sweeten whipped cream, add 1 tablespoon granulated sugar or 2 tablespoons powdered sugar for each cup of cream. A touch of vanilla extract gives a nice flavor. Beat the cream at medium speed. Check frequently to see if the mixture is thickening. The cream should hold stiff peaks. Over beating causes the cream to turn to butter. It is best to whip the cream just before using. It may break down if allowed to stand in the bowl too long.