Directions1. Bake cake according to package directions for two layers.
2. While cake is baking, mix condensed milk with lemon juice and refrigerate.
3. Cool layers completely, then split each layer in half, making four thin layers.
4. Place one layer on a serving plate, then spread with the milk-juice mixture.
5. Place another layer on top and spread with mixture.
6. Place the third layer on these and spread with mixture.
7. Combine the remaining mixture with the whipped topping and use to frost the sides and top.
8. Keep covered and refrigerated.