Baking-powder is a mixture of cream of tartar, bicarbonate of soda, and arrowroot. The latter is used to keep the two chemicals dry, and thus prevent the slow union which would otherwise take place. Sometimes tartaric acid is used instead of cream of tartar. The following rule may be relied upon:
| Tartaric acid | 2 oz. by weight. |
| Bicarbonate of soda | 3 " " " |
| Arrowroot | 3 " " " |
Mix and sift together thoroughly. Keep in a dry place, in a wide-mouthed bottle.
CAKE
Cake of the simpler kinds, especially sponge cake, is frequently given to the sick. Good sponge cake, served with sweet cream or a glass of milk, is an excellent lunch for an invalid. Some of the plain kinds of butter cakes—those made with a little butter—such as white, feather, and similar varieties, are excellent food.
Consider for a moment what they contain: eggs, milk, butter, sugar, and flour—five of the most valuable of all our food products. Yet there are those who pride themselves upon not eating cake, which idiosyncrasy can only be explained in one of two ways: either the cake which they have had has not been properly made, or else it has been so good that, during a lapse of judgment, they have eaten too much.
The dark fruit cakes should be avoided by both sick and well, on account of the indigestible nature of the dried fruits used in them, and also because they are often compact and close-grained, not light.
There is a custom prevalent in many kitchens of using what is called "cooking" butter—that is, butter which is off taste or rancid—for cake. It is but poor economy, even if it can merit that name at all. If you have no other butter for cake, don't make any. Sweet butter and fresh—not "store"—eggs are absolutely necessary. Also, a dainty worker to mix the ingredients with accuracy and care, and to oil the pan in which the cake is to be baked, so that the outside shall not taste of fat. Many an otherwise nice cake has been spoiled by oiling the pan in which it was baked with dirty or rancid grease. Use a very little sweet butter or olive-oil.