Preheat your oven to 350 degrees fahrenheit, and spray a 9x13 pan with non-stick spray.

In a large mixing bowl, prepare the yellow cake, according to box directions.

Pour the cake mix into the 9x13 pan and bake according to box directions.

One finished and slightly cooled, use a straw or the end of a wooden spoon to poke holes into the cake, about halfway through.

In a large bowl, mix together 1 box of butterscotch pudding and 2 cups milk. Pour the pudding into the holes and over the top of the cake. Spread it around with a spatula.

Place the cake in the refrigerator for 1 hour to let the pudding set.

After 1 hour, in a large bow, mix together 1 box of butterscotch pudding and the remaining 1 ½ cups milk. Whisk in cool whip. Spread evenly to frost the cake.

Return the cake to the refrigerator to chill for another hour.

Just before serving, top the cake with butterscotch sauce.

Enjoy!