Instructions:

Bake the cake:
Preheat your oven according to the cake mix package instructions. Grease a 9×13-inch baking dish.
Prepare the yellow cake mix as directed on the package and bake in the prepared dish. Let the cake cool for 15 minutes.
Poke holes in the cake:
Using the handle of a wooden spoon or a straw, poke holes all over the cooled cake, making sure the holes go down to the bottom.
Prepare the pudding mixture:
In a bowl, whisk together the vanilla pudding mix and cold milk until smooth. Allow it to thicken slightly, about 2 minutes.
Pour the pudding mixture evenly over the cake, making sure to fill the holes. Spread it evenly over the top with a spatula. Refrigerate for at least 1 hour to let the pudding set.
Make the chocolate glaze:
In a small saucepan, heat the heavy cream over medium heat until it starts to simmer. Remove from heat and add the chocolate chips. Let them sit for 2-3 minutes, then whisk until smooth.
Stir in the corn syrup (if using) and vanilla extract for a glossy finish.
Glaze the cake:
Pour the chocolate glaze over the chilled cake, spreading it evenly with a spatula. Refrigerate for at least 2 hours, or until the glaze is set.
Serve:
Slice and enjoy the Boston Cream Poke Cake, served chilled.