Wash rhubarb, trim and cut into 1/2 inch slices.
Mix cornstarch with a little water to make a stiff paste; set aside.

In a pot, combine rhubarb, water and sugar and simmer until soft. Stir in vanilla. Stirring constantly, add the cornstarch slurry to the rhubarb and cook for 5 minutes, or until the liquid is thick and clear.

Pour into glass serving dish. Whip cream until stiff. Pipe through pastry tube in decorative swirls on rhubarb compote or cover top with spoonfuls of whipped cream.