Preheat the oven to 350 degrees Fahrenheit and spray a 9x13-inch baking pan with baking spray.
Mix the chocolate cake mix, eggs, salted butter, and heavy cream in a large mixing bowl until well combined. The mixture will be thick.
15.25 ounce box chocolate cake mix, 2 large eggs, ½ cup (1 stick) salted butter, ⅓ cup heavy cream
Fold in the dark and milk chocolate chips until evenly distributed.
¾ cup dark chocolate chips, ¾ cup milk chocolate chips
Spread the mixture into the prepared baking pan in an even layer.
Bake for 23-26 minutes or until a toothpick inserted in the center comes out with some goo but not covered in batter.
Remove from the oven and cool completely before cutting into squares and serving.
Notes
Storage:
To Store: Store leftover brownies in an airtight container at room temperature for 2 to 3 days or refrigerate them for up to 1 week.
To Freeze: Freeze the brownies in a freezer safe container for up to 3 months. Thaw them in the refrigerator before serving.
Tips:
Depending on your brand of cake mix, you may create a fudgier or cakier brownie consistency.
Keep in mind that making substitutions to this recipe may affect the texture and taste of the brownies, so be mindful of the changes you make.
Your brownies are done baking when a toothpick poked in the center comes back gooey but not with batter on it.
Make sure you allow the brownies cool completely before cutting them. The center of the brownies may seem a bit undercooked when the pan comes out of the oven. However, they will set up as they cool down.