In medium saucepan, combine sugar and cornstarch; blend well. Stir inraspberries. Cook over medium heat until mixture boils and thickens, stirring constantly. Remove from heat; cool 1 hour or until completely cooled.
Line 1 1/2-quart round bowl with plastic wrap. Place 1 layer bread cubes over bottom and halfway up sides of bowl. Pour small amount of raspberry sauce over bread. Repeat, alternating layers of bread and raspberry sauce, ending with bread on top. Place plastic wrap over top of pudding. Cover with plate that fits tightly inside bowl; place heavy object on top of plate to mold pudding. Refrigerate at least 8 hours or overnight.
Just before serving, remove plate and plastic wrap; unmold onto serving plate. Remove plastic wrap. Frost sides of pudding with swirls of whipped cream.