In a small heavy saucepan, combine whipping cream and sugar. Cook and stir over medium heat until sugar dissolves. Remove from heat; set aside.
In another small saucepan, combine water and gelatin. Let stand for 5 minutes to soften. Heat and stir over medium heat till gelatin dissolves. Stir gelatin mixture into whipping cream mixture; transfer to a medium bowl. Stir sour cream and vanilla into cream mixture; mix well.
Cover and chill in the refrigerator for 30 to 45 minutes or till mixture thickens like the consistency of yogurt. (Or can place gelatin mixture in a bowl of ice water and chill about 25 to 30 minutes, stirring occasionally.)
4.Layer cream mixture and Raspberry Sauce in each of 6 parfait, martini, or wine glasses, ending with Raspberry Sauce; swirl sauce into the cream with a thin metal spatula. Cover and chill in the refrigerator for at least 2 hours and up to 4 hours. Top with fresh raspberries just before serving.
Raspberry Sauce - Place 1-1/2 cups raspberries in a blender or food processor. Cover and blend or process till berries are pureed. Press berries through a fine-mesh sieve; discard seeds. Repeat with 1-1/2 cups more berries. (You should have about 1 cup sieved puree.)
In a small saucepan, stir together sugar and cornstarch. Add sieved berries and lemon juice. Cook and stir over medium heat till thickened and bubbly.
Cook and stir for 2 minutes more. Remove from heat. Cool to room temperature.