This is a classic, simple Vanilla Sponge that is made with basic ingredients eggs, milk, butter, flour, sugar, vanilla, baking powder and salt. Thats it. No sour cream, no buttermilk these are not pantry staples in my world or any other schmancy ingredients. Yes adding sour cream and/or buttermilk makes an even more tender, more moist cake. But I wanted to share a truly great Vanilla Sponge Cake that is made with just pantry staples.. INGREDIENTS eggs, milk, butter, flour, sugar, vanilla, baking powder and salt.