Preheat your oven to 350°F and grease two 9-inch round cake pans.
In a large bowl, whisk together sugar, flour, cocoa powder, baking powder, baking soda, and salt.
Add eggs, milk, oil, and vanilla. Mix until smooth.
Slowly stir in boiling water. Batter will be thin—don’t worry, it’s supposed to be.
Pour evenly into prepared pans and bake for 30-35 minutes or until a toothpick comes out clean.
Let cakes cool in the pans for 10 minutes, then remove to wire racks to cool completely.
Frost with your favorite chocolate frosting (or just eat it plain—we’re not judging).