Red, White 'n' Blue Salad

Dissolve berry blue gelatin in 1 cup boiling water; stir in 1 cup cold water. Add blueberries. Pour into a 3-qt. serving bowl. Refrigerate until firm, about 1 hour. , In a saucepan, sprinkle unflavored gelatin over 1/2 cup cold water; let stand for 1 minute. Add cream and sugar; cook and stir over low heat until dissolved. Cool to room temperature. Whisk in sour cream and vanilla. Spoon over blue layer. Refrigerate until firm., Dissolve raspberry gelatin in remaining hot water; stir in remaining cold water. Add raspberries. Spoon over cream layer. Chill until set. Top with whipped topping and berries if desired.