Maple Icing
1 3/4 cups maple sirup 1/4 cup granulated sugar 1 egg white Boil the sugar and sirup together till a heavy thread is formed when a spoon is dipped in the sirup and lifted, or to 244 degree F. Then pour it in a fine stream on the beaten egg white, beating the white as the sirup is poured in. Set the bowl which contains the mixture on a dish of hot water, and beat the mixture thoroughly till the egg stiffens somewhat, then spread on the cake. One-half cup of coarse chopped nuts may be mixed with the frosting, if desired. Also a little vanilla flavoring may be used.
This is an Italian-meringue-style frosting made with maple syrup instead of a plain sugar syrup. The hinge is the syrup temperature: pull it early and the icing never sets, take it past the mark and it turns grainy and stiff before you can spread it.
- 244F is firm-ball244F sits at the soft-ball/firm-ball boundary -- a candy or instant-read thermometer is more reliable than judging the thread by eye. At 244F the icing should set firm but stay spreadable.
- Maple syrup grade"Maple sirup" here means boiled maple sap rather than a maple-flavoured table blend, though blended and adulterated syrups were also sold in this period. A darker, stronger-tasting syrup gives more maple flavour.
- Volume of syrup1 3/4 cups of syrup boils up dramatically. Use a saucepan at least three times the volume of the liquid and do not stir once it is boiling.
- Pouring the syrupBeat the egg white to soft peaks first, then add the syrup in a thin stream down the side of the bowl with the beater running. A stand mixer or hand mixer makes this a one-person job; with a whisk you need a second pair of hands.
- The dish of hot waterThe dish of hot water is a warm-water bath, not a double boiler over heat. Its purpose is to keep the meringue fluid while you beat it to body.
- Nuts and vanillaFold the half cup of chopped nuts in at the very end, once the icing holds its shape, or they will deflate it. A teaspoon of vanilla is the usual quantity for this volume.
- Yield and timingThis makes enough to fill and cover a two-layer 8- or 9-inch cake. Spread it as soon as it holds a peak; boiled frostings of this kind crust as they stand.
- StorageKeep the finished cake at room temperature under a cover. Refrigeration makes this style of frosting weep.