Prepare and bake cake according to package directions, using a greased 13x9-in baking pan. Cool; cut into 1-in. cubes.
In a small bowl, combine orange juice and sherry. In another bowl, whisk jam. In a large bowl, whisk milk and pudding mix for 2 minutes. Whisk in sour cream. Let stand for 2 minutes or until soft-set.
Divide half of the cake cubes among 15 parfait glasses or dessert dishes; drizzle with half of the orange juice mixture. Layer each with jam and pudding mixture. Top with remaining cake cubes; drizzle with remaining orange juice mixture. Cover and refrigerate for at least 4 hours or overnight.
Just before serving, in a large bowl, beat cream until it begins to thicken. Add confectioners' sugar; beat until stiff peaks form. Dollop over trifles and garnish with raspberries.