In a large bowl, beat cream cheese and yogurt. Add the milk, dry pudding mix and lemon zest; beat until smooth. In a blender, process 1/2 cup strawberries and grape juice until blended. , Tear cake into 1-in. cubes; place a third in a trifle bowl or 3-qt. serving bowl. Top with a third of the pudding mixture and half of the remaining strawberries. Drizzle with half of the strawberry sauce. Repeat all layers. Top with remaining cake and pudding mixture. If desired, garnish with whipped topping and additional strawberries. Cover and refrigerate for at least 2 hours.