Easy to make, grandma's German marble cake is a family favorite.
Achieving a light, tender crumb in this cake hinges on proper aeration. When creaming butter and sugar, aim for a very light, fluffy consistency; this incorporates crucial air. The extended beating of egg yolks further emulsifies the mixture and builds structure. When incorporating flour and milk, alternate additions gently to prevent overworking the gluten, which can lead to a tough cake. The most critical step for texture is folding in the beaten egg whites. Do this delicately, using a rubber spatula, to preserve the air bubbles, which are vital for the cake's lift. For the marble effect, create just a few swirls with a fork, avoiding excessive mixing that blurs the contrast. Ensure your tube pan is meticulously greased and floured; a quick chill of the pan after prep can help the flour adhere better. Always trust the toothpick test for doneness, as oven temperatures can vary.