MIX 3/4 cup sugar and 1-1/2 tsp. cinnamon in medium bowl. Combine COOL WHIP and remaining cinnamon; refrigerate until ready to use.
BRING water, butter and remaining sugar to boil in medium saucepan on medium-high heat. Stir in flour; cook on low heat 1 min. or until mixture forms a ball, stirring constantly with wooden spoon. Transfer to medium bowl. Add eggs, 1 at a time, beating with mixer after each until well blended. Add sour cream; mix well.
HEAT oil in large saucepan to 350ºF. Spoon dough into heavy-weight pastry bag fitted with medium-star tip. (Or spoon into a cake decorator's tube fitted with star tip.) Carefully squeeze 3 or 4 (4-inch-long) strips of dough into hot oil; cook 2 to 3 min. or until golden brown on both sides, turning after 1 min. Remove from oil with slotted spoon; drain on paper towels. Repeat with remaining dough.
ROLL in cinnamon sugar while still warm. Serve with COOL WHIP mixture.