Published January 1, 1994.
In developing our pudding cake recipe, we baked some 15 pudding cakes, noticing that those made with lemon or orange juice came out especially well, while those flavored in other ways tended to have flimsy, fast-dissolving tops and rubbery, dense bottoms. We eventually deduced that it was the acidity of the citrus juices that made the difference. Because the juice lightly clabbered the milk-based batter, causing it to thicken, the frothy upper layer became stiffer and more stable and thus better able to puff. At the same time, the acidic juice undercut the thickening power of the flour, making a more tender custard. To shore up the cake part of those pudding cake recipes made with coffee, chocolate, and vanilla, we added an extra egg white.