Home › Cakes › Marshmallow Filling
Marshmallow Filling
5 tablespoons boiling water 1/2 teaspoon vanilla White of 1 egg 8 marshmallows Beat the white of the egg until stiff and heat the marshmallows until soft. Boil the sugar and water until it spins a thread; pour on the egg and marshmallows and beat until cool enough to spread. • •
A boiled-syrup frosting in the Italian meringue family, thickened further with melted marshmallow. The printed ingredient list omits the sugar quantity even though the method calls for it, so some judgment is required.
- The missing sugarThe instructions say to boil sugar and water, but no amount is given. For 5 tablespoons of water, roughly 3/4 to 1 cup of granulated sugar gives a syrup of about the right proportion, but the original figure is genuinely unrecoverable.
- "Spins a thread"Thread stage is 230-235F on a candy thermometer. Below that the filling stays soupy and weeps; much above it and the frosting sets hard and crumbles as you spread it.
- Order of operationsHave the egg white already at stiff peaks and the marshmallows already soft before the syrup reaches temperature. Syrup does not wait, and beating egg white while pouring hot sugar is a two-hand job — a stand mixer earns its place here.
- Softening the marshmallowsA heatproof bowl set over simmering water, or short bursts in a microwave, is enough. Direct heat scorches the sugar in them and turns the filling grainy and brown-flecked.
- Marshmallow sizeEight marshmallows meant the shop or homemade gelatin squares of the period, whose size is not documented here; if taken as today's standard bagged marshmallows that is about 2 oz total, or roughly 80 miniatures.
- Egg whiteThe hot syrup brings the white up substantially but not reliably to a pasteurizing temperature. Use pasteurized whites if serving anyone who should avoid raw egg.
- Working time and yieldBeat only until it holds a soft shape and is barely warm; it firms as it cools and becomes unspreadable if you wait. Assuming about a cup of sugar, it should make roughly enough to fill and lightly top one 8- or 9-inch two-layer cake.
Marshmallow began as a medicinal paste made from the mucilaginous root of Althaea officinalis, and was made as a confection from that root before manufacturers substituted gelatin and whipped sugar in the later nineteenth century. By the time this leaf was printed, marshmallows were an inexpensive packaged staple, and American cake books carried numerous ways to melt them into frostings, fudges and puddings — a shortcut to the glossy, stable meringue that otherwise demanded careful sugar boiling. Loose-leaf cook books such as this one were sold as binders so that a household could add pages and paste in clippings.