Preheat your oven to 350 degrees F.
Grease a 9x13 baking dish (You can use butter, oil, or cooking spray. I use butter as it gives a nice taste to the crust)
In a large mixing bowl, pour the Yellow cake mix, water, olive oil, and eggs.
Mix until all ingredients are combined. I used a hand mixer, but you could do it in a stand-up mixer or with a wooden spoon. The trick is as soon as the ingredients are all incorporated, stop mixing.
Pour the batter into the prepared 9x13 dish and bake in a preheated oven for 28 to 30 minutes. The edges are set and when inserting a toothpick in the middle it comes out clean.
Let the cake cool completely.
With a large straw or the back of a wooden spoon, make holes throughout the cake. I like to make 5 rows by 12.
In a microwavable safe bowl, melt your butterscotch chips, and milk. Be careful, you don’t want to overheat the milk. So, I use my microwave at 50% powder and mix in 30 seconds increments.
Once the butterscotch is all melted and mixed with the milk, you will have butterscotch milk, add the Vanilla Jell-O pudding. Whisk it together.
Pour evenly over the cake.
With an offset spatula spread so it can go into every hole.
Set aside until it sets. I put mine in the fridge for 30 minutes, but you can leave it in the fridge overnight.