Gather all the ingredients, and preheat the oven according to the cake instructions.
Prepare yellow cake in a 9x13-inch baking pan according to package instructions. Let cool completely. A toothpick inserted into the center of the cake should come out cleanly.
1 box yellow cake mix, 3 eggs, 1 cup milk, ½ cup olive oil or vegetable oil
While the cake is cooling, make the pudding. In a large bowl, whisk the cold milk, vanilla, and pudding mix until smooth. Continue to whisk for about 2 minutes or until the pudding becomes thick.
4 cups milk, ½ teaspoon vanilla extract, 2 boxes instant vanilla pudding mix
Use the handle of a spoon or your finger (wash your hands first!) to poke holes in the cake. You want to poke a hole every 1-2 inches across the entire surface of the cake.
Scoop the pudding onto the cake and spread it evenly across the whole cake, making sure the pudding goes down into the holes. Push the pudding into the holes as you spread.
Make the chocolate glaze next. Add the chocolate chips and cornsyrup to a large mixing bowl. Bring the heavy cream to a boil then pour the hot cream over the chocolate chip. Let the bowl sit for one minute, allowing the cream to melt the chocolate chips. Then, whisk until smooth.
1½ cups chocolate chips, 1 tablespoon corn syrup, ¾ cup heavy cream
Pour the chocolate glaze over the entire cake in the pan. Spread the glaze evenly across the top of the cake.
Slice and serve the cake immediately or cover the dish with plastic wrap, then chill the cake in the fridge.