Preparation Steps

• Preheat the oven to 350°F. Coat a 9x13-inch baking dish with nonstick spray and set aside.
• Prepare the cake according to package directions using the oil, water, and eggs. Pour the batter into the prepared pan.
• Bake for 25-30 minutes, or until a toothpick inserted in the center comes out clean.
• Place the cake on a wire rack and let it cool completely.
• Use the back of a wooden spoon to poke holes evenly across the surface of the cake, going about halfway down.
• In a small saucepan or microwave-safe bowl, combine the sweetened condensed milk and semi-sweet chocolate chips. Heat gently, stirring until smooth and fully melted.
• Pour the melted chocolate mixture evenly over the cake, ensuring it fills the holes. Let sit for 10 minutes.
• In a large bowl or stand mixer fitted with the paddle attachment, beat the softened butter, cocoa powder, and powdered sugar on low until combined. Add milk and mix on low, then increase to medium speed and beat for 1 minute until creamy and smooth, scraping the bowl as needed.
• Spread the frosting evenly over the top of the cooled cake.
• Garnish with mini chocolate chips if desired. Chill for 30 minutes to set before serving. Store leftovers covered in the refrigerator.