Dutch-processed cocoa gives this cake even more chocolate flavor. We’ll “choc” that up as a win.
Have you heard about our Young Chefs’ Club? Members get a themed (and kid-tested) box delivered each month!
Adjust oven rack to middle position and heat oven to 325 degrees. Spray bottom and sides of 13-by-9-inch metal baking pan with vegetable oil spray.
Spraying the pan over the sink helps keep things clean.
In medium bowl, whisk together sugar, flour, baking soda, and salt.
In large saucepan, combine chocolate chips, milk, and cocoa. Place saucepan over low heat and cook, whisking often, until chocolate chips are melted and mixture is smooth, about 5 minutes.
Add oil, eggs, and vanilla to saucepan with chocolate mixture and whisk until smooth, about 30 seconds.
Use rubber spatula to scrape batter into greased baking pan and smooth top (ask an adult for help because saucepan will be heavy).
Place baking pan in oven. Bake until toothpick inserted in center comes out with few crumbs attached, 30 to 35 minutes.
The cake is done when a toothpick inserted in the center comes out looking like this—with just a few crumbs sticking to it.
Use oven mitts to remove baking pan from oven (ask an adult for help). Place baking pan on cooling rack and let cake cool completely in pan, about 2 hours.
Use icing spatula to spread frosting evenly over cooled cake. Cut cake into pieces and serve.
Use rubber spatula to mound frosting in center of cake. Then use icing spatula (also called an offset spatula because the blade isn’t straight) to spread frosting evenly to edges of cake.