For cake batter:

1. Prepare cake batter and bake in 13 x 9-inch baking pan as directed on package. 
2. Cool completely on wire rack. 
3. Cut into 1/2-inch cubes.

For pudding:

1. Add milk to dry pudding mix in medium bowl. 
2. Beat with wire whisk 2 minutes or until well blended. 

For trifle:

1. Layer half of the cake cubes in large glass trifle bowl.
2. Layer half of pudding.
3. Layer half of whipped topping.
4. Layer half of crushed chocolate bar. 
5. Repeat all layers. 
6. Serve immediately or cover and refrigerate until ready to serve.