In warm weather particularly, it is important that the cream and mixing bowl for whipped cream be chilled. Add the cream to the mixing bowl and beat rapidly with a wire whisk, electric mixer, or rotary beater until mixture stands in peaks. Then beat in the sugar and vanilla. As the cream becomes increasingly frothy and thickened, lift the beater to test for thickness. The completed cream must be quite thick, but you must exercise caution. If you beat the cream too thoroughly for too long a time it will turn to butter.