In Britain, coffee cake means a round layer cake that is made with a coffee-infused sponge and coffee-infused buttercream frosting with chopped walnuts mixed in or used to decorate the top of the cake. My Gluten-Free Vegan Coffee Walnut Cake is an example of this. This Vegan Coffee Cake recipe is an American coffee cake, which does not contain coffee. It is called coffee cake because it is a cake that is often eaten with coffee. American coffee cake consists of a vanilla sponge, which is traditionally made extra moist and fluffy by the addition of sour cream, buttermilk, yogurt or cream cheese and topped with a cinnamon-infused crumble (streusel) topping. A mixture of cinnamon and sugar is also often added to the middle of the sponge to create a swirl effect. This eggless, dairy-free coffee cake it is made using a dairy-free buttermilk substitute.