No. 100

Cooked Cocoa Icing

Glace Cuite au Cacao

Dissolve a quarter of a pound of cocoa or unsweetened chocolate in a sugar-pan; cook three quarters of a pound of sugar in another pan with one pint of water till it reaches the degree of small thread, mash the cocoa with a spoon, dilute it gradually with the cooked sugar, then cook all together until it reaches small thread again; remove it from the fire, rub it against the sides of the pan with a spoon in order to mass it well; this icing is used to ice Genoese, eclairs and a variety of small cakes.

← No. 99 Cooked Chocolate Icing Elementary Methods No. 101 Royal Icing, and Royal Icing Flavored with Z →

For the Modern Kitchen

A cooked fondant-style icing built on sugar syrup rather than butter or confectioners' sugar. The whole thing turns on hitting the thread stage twice and then working the mass with the spoon while it cools.

The hinge: rubbing against the panWorking the hot syrup against the side of the pan with a spoon forces small sugar crystals, which is what makes the icing set opaque and firm rather than drying to a sticky glaze. Skip it and you have chocolate syrup that never sets.
"Small thread" in degreesPetit file is usually put at roughly 217-221F (103-105C), though period tables vary and modern candy-thermometer "thread stage" is often given higher. The traditional gauge was the finger test: syrup pulled between finger and thumb spins a short thread that breaks. A thermometer is more reliable and safer.
QuantitiesA quarter pound of cocoa is 4 oz (about 1 cup of modern cocoa powder, or 4 oz chopped unsweetened chocolate); three quarters of a pound of sugar is 12 oz, a scant 1 3/4 cups. The pint of water is mostly boiled away.
Cocoa versus chocolateThe recipe offers them as alternatives, but they do not behave alike. Unsweetened block chocolate carries about 50 percent cocoa butter and will melt to a fluid mass; cocoa powder, Dutch or natural, holds only around 10-12 percent fat and needs a few spoonfuls of the hot syrup worked in first to make a smooth paste, or it stays gritty.
"Sugar-pan"An unlined copper poêlon, heavy and untinned so it tolerates the heat of boiling syrup. A heavy stainless or copper saucepan with a thick base does the same job; thin aluminium scorches the cocoa.
Working temperatureThe icing sets fast once it grains. Keep it over a pan of warm water while you glaze, and thin it with a spoonful of hot water or sugar syrup as it stiffens rather than reheating it hard, which dulls the finish.
Second cookingAfter the cocoa goes in, the mixture spits and thickens unevenly. Stir constantly and take it off the heat the moment the thread returns — a few degrees past and the icing sets hard and dull on the cake.
YieldRoughly a cup and a half of icing, enough to glaze a couple of dozen eclairs or a few Genoise layers thinly, depending how heavily you coat them.

A Little History

This is No. 100 from the Elementary Methods section of Charles Ranhofer's The Epicurean (1894), the vast compendium written by the chef of Delmonico's in New York. The numbered method entries were meant as building blocks. It sits immediately after No. 99, a chocolate version, and the recipe itself offers cocoa and unsweetened chocolate as straight alternatives in the same line. The technique itself is straight fondant work, French in origin, and the deliberate graining of a cooked syrup is the same principle behind poured fondant and the older sugar glazes it replaced.