Home › The Principles of Cookery › Almond Icing for Cakes
Almond Icing for Cakes
Blanch one pound of sweet almonds and eight bitter almonds. Pound them in a mortar to a smooth paste, and drop in once or twice during the process a very little orange-flower water. Add to them one pound of sifted sugar, and as much white of egg as will make a soft stiff paste. When all are well mixed together, lay the icing on the top of the cake, already baked, a little more than half an inch thick, as smoothly and evenly as possible. Put it in a cool place to dry. The sugar icing goes over this (see ICING, SUGAR). Time to dry, about one day. Probable cost of almonds, 1s. to 2s. 6d. per pound.
This is a raw almond paste — marzipan laid under royal icing — and the problem is the eight bitter almonds, which are not a flavouring you can simply substitute in and out of a recipe that is never cooked.
- Bitter almonds are the reason to stopBitter almonds are the reason for caution -- Bitter almonds contain amygdalin, which releases hydrogen cyanide when the kernel is crushed and wetted, which is what pounding in a mortar with orange-flower water does. Eight kernels to a pound of sweet almonds is the usual period flavouring proportion and the amount reaching any one slice is small, but it is a genuine toxin in a paste that is never cooked, and children are more susceptible than adults.
- Nothing here destroys the toxinNothing here reliably destroys the toxin -- Blanching in hot water skins the nut and will leach or partly deactivate some of what causes the trouble, but it is not a step designed to remove amygdalin, and this paste then goes onto an already-baked cake and is left to dry for a day. Nothing in the method cooks it.
- You cannot buy them anywayUnprocessed bitter almonds are not legally sold for eating in the United States and are restricted in many other countries. What is sold as "bitter almond" today is normally an extract or oil from which the hydrogen cyanide has been removed, which is not the same ingredient the recipe assumes.
- Raw egg whiteThe paste is bound with uncooked white of egg and then left to dry for about a day (the recipe says in a cool place) under a second layer of icing. It is never heated, so it carries the usual low but real raw-egg risk, which period cookery had no way to account for.
- What to do insteadUse a current marzipan or almond-paste recipe. Modern versions get the same perfumed bitterness from a few drops of commercial almond extract, and pasteurised egg white where a binder is wanted.
- Reading the originalOrange-flower water is still sold and still used the same way. The costing in shillings per pound is a Victorian price note, not a measurement, and tells you only that almonds were an expensive luxury.
Almond paste under a hard sugar shell is the standard English finish for a rich fruit cake, and Cassell's treats the two icings as a pair — the marzipan seals the cake and gives the royal icing a flat surface to sit on, which is why it is laid "a little more than half an inch thick" and left a day to skin over. The eight bitter almonds are the period's flavouring habit: before commercial extracts, the marzipan almond taste came from adding a few genuinely bitter kernels to a pound of sweet ones, a practice found across nineteenth-century European confectionery and one that survived into twentieth-century recipes long after the chemistry of amygdalin was understood. The same logic explains why old ratafia biscuits, noyau and macaroon recipes so often call for a small proportion of bitter almonds or apricot kernels; the flavour compound and the toxin travel together in the same nut.