1 (1.4-oz.) pkg. fat-free, sugar-free chocolate instant pudding mix
2 c. 1% low-fat milk
1/2 cup light sour cream
1 (8-oz.) container fat-free frozen whipped topping, thawed and divided
3/4 cups chocolate graham cracker crumbs (4 cracker sheets)
1 Tbsp. freshly grated chocolate
Whisk together first 3 ingredients in a bowl until blended and smooth. Fold in 1-1/2 cups whipped topping. Spoon 1 Tbsp. crumbs into each of 6 (4-oz.) glasses, and top with 1/3 cup pudding mixture. Repeat layers with remaining crumbs and pudding mixture. Top each parfait evenly with remaining whipped topping and grated chocolate. Cover and chill at least 1 hour.