Place 2 cups strawberries in a large mixing bowl, set aside.
Mash 1 cup of the strawberries.
Combine mashed and unmashed strawberries, sugar and cornstarch in a saucepan. Cook over medium heat until thickened, stirring constantly. Stir in Grand Marnier; cover and chill.
After thoroughly chilled, mix with strawberries (set aside), Jell-O, and Cool Whip. Refrigerate.
Makes: 4