No, we don't recommend it. While both milk and buttermilk will make cakes extra moist, buttermilk or homemade buttermilk plus the addition of more apple cider vinegar are necessary acids in this recipe. We need additional acid in this recipe because we are using black cocoa instead of natural cocoa. Black cocoa powdered is alkalized, so we need to add more acid to contribute to the leavening, tender texture and lovely taste of this cake. In other words, don't skip buttermilk or homemade buttermilk and the apple cider vinegar!