Beat all the wet ingredients in a mixer with the paddle attachment. Once the wet ingredients are combined, add in all of the dry ingredients, adding in the chocolate chips last.
Pour into a greased 9×13 baking pan.
Bake at 350º for 25+ minutes, or until a toothpick comes out clean.
Cool and ice with cream cheese frosting (see below) and drizzle with melted chocolate.
Mix cream cheese and the softened butter in a mixer with the paddle attachment until well incorporated. Add in the vanilla.
Slowly add in the powdered sugar, a little at a time, until the desired consistency is reached.
