Preparation Steps

• Preheat the oven to 350°F (175°C). Grease and flour a 9x13-inch baking pan or line it with parchment.
• In a large bowl, whisk together the yellow cake mix and instant vanilla pudding until evenly combined.
• Add the eggs, sour cream, vegetable oil, melted butter and vanilla extract to the dry mix. Beat with a hand mixer on medium speed until the batter is smooth and no dry pockets remain, about 2 to 3 minutes.
• Fold in 1 1/2 cups of the chocolate chips by hand, reserving the remaining 1/2 cup for topping.
• Pour the batter into the prepared pan and spread into an even layer. Sprinkle the reserved chocolate chips evenly over the top.
• Bake for 30 to 35 minutes, or until a toothpick inserted into the center comes out with a few moist crumbs (not wet batter). Allow the cake to cool in the pan on a wire rack for 15 minutes.
• While the cake cools, whisk together powdered sugar and milk to make a smooth glaze. Adjust thickness by adding more milk a teaspoon at a time if needed.
• Drizzle the glaze over the warm cake, allow it to set for at least 10 minutes, then cut into 12 slices and serve.