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Mocha Cake
Take half a pound of fresh butter, four ounces of powdered sugar, and work them well together. When they are well mixed, add the whites of two. When the mixture is thoroughly well done, add, drop by drop, some boiling coffee essence to your taste. Butter a mold and line it with small sponge biscuits, and fill it with alternate layers of the cream and of biscuits. Put it for the night in the cellar before you serve it the following day. You can replace the essence of coffee by some chocolate that has been melted over hot water.
This is an uncooked butter cream set in a lined mold — a charlotte-style icebox cake. The method depends on raw egg white that is never heated, which is why it cannot be recommended as written.
- Why the cautionThe whites go into cold, creamed butter and are never brought to any temperature at all. The few drops of hot coffee essence added last are far too little to raise the mass; the cake then stands overnight in a cool cellar, which is a holding temperature rather than a killing one. Raw white carries a Salmonella risk that resting for a day does not reduce. Use a current recipe for coffee buttercream or an icebox charlotte, one built on a cooked custard, a hot-syrup meringue or pasteurised whites.
- The cellarA cellar ran cooler than the kitchen but well above the 40F of a modern refrigerator. The overnight rest was for setting the butter and letting the layers soften into one another, but for a butter-and-egg cream it is also the part of the process that is furthest from modern food-safety practice.
- "The whites of two"The original sentence is incomplete — two of what is never stated, though eggs are plainly meant. Note also that nothing is done to them: they are not beaten to a meringue, merely added to the creamed butter.
- Weights and vesselsHalf a pound of butter is two US sticks; four ounces of powdered sugar is a weight, roughly a cup by volume, though 'powdered sugar' at the period meant finely ground sugar rather than necessarily modern confectioners' sugar. The mold's shape is not specified; it is buttered so the assembled cake can be turned out.
- Small sponge biscuitsThese are ladyfingers of the dry Continental kind (boudoirs, savoiardi), not soft sponge cake. They were meant to knit with the cream into a sliceable whole.
- Coffee essenceA thick coffee concentrate, often sweetened, of the kind sold bottled in Britain at the period, or made at home by reducing very strong coffee — the recipe's 'boiling' essence suggests the latter. Modern espresso or instant coffee paste stands in for it in current recipes; the point of the drop-by-drop addition was to flavour without loosening the butter.
The Belgian Cook Book was assembled in 1915 from recipes contributed by Belgian refugees who had fled to Britain after the German invasion, and it reads like a kitchen carried out in a suitcase: household dishes recorded from memory, with the loose measurements and half-finished sentences of dictation. "Mocha" here means coffee-flavoured, the name generally traced to the Yemeni port of Mocha, long the trading name for the coffee that came through it; by the late nineteenth century mocha buttercream was standard in French and Belgian p u00e2tisserie. The construction — a buttered mold lined with dry sponge biscuits and packed with alternate layers of cream, then left to set in a cool place overnight — belongs to the charlotte family, and it anticipates something of the twentieth-century icebox cake. That it needs no oven mattered: a dish like this could be made in a borrowed kitchen with a cellar and no more.