Step 1

Prepare and bake the cake in a 13x9 pan according to the package instructions. Let cool for 15 minutes before poking holes across the cake with the bottom of a wooden spoon. Be sure to poke all the way to the bottom of the pan.

Step 2

In a large bowl, whisk together pudding, milk and vanilla for 2 minutes. Pour over cake in an even layer, poking down into the holes if necessary. Refrigerate while preparing chocolate glaze.

Step 3

Place the chocolate chips and corn syrup in a heat-proof bowl. In a small saucepan over low heat, warm the cream until it simmers, stirring occasionally. Pour over chocolate chips and let sit for 2 minutes to melt. Whisk until smooth. Let cool for 10 minutes, then pour over cake and smooth with a spatula. Chill cake for 4 hours or overnight before serving.