Soften gelatin in cold water.
Sieve un-drained plums into saucepan; bring to boil.
Stir in softened gelatin and lemon juice.
Add food coloring, if desired.
Stir till dissolved.
Chill till partially set (consistency of unbeaten egg whites).
In large mixer bowl beat egg whites with salt till soft peaks form; gradually add plum mixture and beat till fluffy.
Prepare topping mix according to package directions; fold half into plum mixture, Chill till partially set.
Mound into individual serving dishes; chill.
Use remaining topping as garnish.