2. Let remaining ¼ cup milk sit till lukewarm. To this remaining milk, add 1 tbsp. sugar and 2 yeast cakes, crumbled. Mix until there are no lumps. Cover, and let form a sponge, no liquid will be left on the bottom. After the sponge forms, add to the flour & milk mixture above, cover with a pot lid or dish towel and sit aside for ½ hour until sponge bubbles.