Cake: Sponge
Lemon Sponge Cake.
Yolks 2 eggs, 1 cupful sugar, cupful hot water, 1 teaspoonful lemon juice, Grated rind 1 lemon, 1 cupful flour, CAKE 1½ teaspoonfuls Calumet baking powder, teaspoonful salt, Whites 2 eggs.
Beat yolks till light-colored and thick, add half the sugar gradually, and continue beating; then the hot water, the rest of the sugar, the lemon juice and rind. Beat well, add flour, mixed with baking powder and salt; lastly cut and fold in the stiffly beaten whites of eggs. Put in shallow greased and floured pan, and bake in a moderately hot oven twenty-five minutes.
A hot-water sponge leavened with both baking powder and beaten whites — lighter and more forgiving than a true whipped-egg sponge, but the printed fractions have dropped out in a few places.
- Missing fractionsThe typesetting has lost some quantities: "cupful hot water" and "teaspoonful salt" were probably ½ cupful and ¼ teaspoonful in the original. A full cup of water against one cup of flour would give batter, not cake; treat the water as ½ cup and the salt as a scant ¼ teaspoon.
- Oven temperature"Moderately hot" in this period is usually taken as somewhere around 375F. Twenty-five minutes at that heat suits a shallow pan; the cake is done when the top springs back and a skewer comes out dry.
- Pan size"Shallow" means a layer or jelly-roll depth, not a loaf. An 8-inch square or 9-inch round pan gives the right thickness; in anything deeper the centre will stay damp while the edges set.
- Calumet baking powderCalumet was a double-acting powder of the SAS-phosphate type. The brand name in the ingredient list points to a commercially supplied recipe, though that cannot be confirmed from the page itself. Any modern double-acting baking powder works at the same 1½ teaspoons.
- The hot waterAdding hot water to the beaten yolks is central to the method: it loosens the foam so the sugar dissolves and helps give an open crumb. Add it in a slow stream while beating.
- Folding the whitesFold the whites in after the flour, in two or three additions, cutting down and turning over rather than stirring. Beat them to firm but still glossy peaks — dry, crumbly whites will leave white streaks that no amount of folding removes.
- LemonOne teaspoon of juice is for flavour balance only; the grated rind carries the aroma. Zest the lemon before juicing it, and rub the zest into the sugar if you want a stronger perfume.
- YieldA two-egg cake of this size serves six to eight. It is best the day it is baked; sponges of this type stale quickly.
Hot-water sponge cakes belong to the era when chemical leavening had become cheap and reliable but the sponge tradition — cake risen on beaten eggs alone — was still the standard of elegance. The compromise gave home bakers a light crumb without half an hour of hand-beating, and the hot water dissolving the sugar was the trick that made a small number of eggs go far. The naming of Calumet baking powder in the ingredient list is the giveaway about how this recipe travelled: baking powder companies distributed recipe leaflets and cookbook pages in the first decades of the twentieth century, and compilations of household knowledge took them up, brand name and all.