Place the diced rhubarb in a heavy, noncorrosive pot with 1 cup of the
sugar and cook on a low heat, stirring occasionally, until the
rhubarb is soft. Set aside 1/2 c of this mixture. Puree the remaining
rhubarb through a food mill and cool.

Soften the gelatin in the lemon juice and dissolve over boiling water
in a double boiler. Add the gelatin to the rhubarb puree and stir
well. Whip the cream, and flavor with the remaining 1/4 cup sugar and
vanilla. Flod the whipped cream into the rhubarb puree, alternating
with the unstrained rhubarb.

Ladle the mixture into 1 large or 6 small, lightly oiled decorative
molds. Refrigerate several hours or overnight. Unmold and serve as
is, or with creme anglaise, fresh mint, and a dollop of whipped cream.

Blueberries can be used instead of rhubarb. Then use 1 1/4 lbs and
reduce the amount of sugar to 1/2 cup.