Preheat oven according to cake mix package directions. Prepare and bake yellow cake mix in a greased 9x13 inch pan following package instructions.

While cake is still warm, use the handle end of a wooden spoon to poke holes evenly across the entire surface, spacing them about 1 inch apart. Poke all the way to the bottom of the pan.

In a large bowl, whisk together the instant pudding mix and cold milk for 2 minutes until mixture begins to thicken. Let sit for 2-3 minutes.

Pour pudding mixture evenly over the warm cake, using a spatula to spread it into all the holes. Refrigerate for 2 hours until pudding is set.

For the ganache, heat heavy cream in a microwave-safe bowl until just simmering, about 90 seconds. Pour over chocolate chips and let sit for 1 minute without stirring.

Whisk ganache until smooth and glossy. Let cool for 5-10 minutes until slightly thickened but still pourable.

Pour ganache over the chilled pudding layer and spread evenly. Refrigerate for at least 1 hour before serving.