Fudge with Marshmallow Cream

A plain water fudge — no milk, no butter — that relies on marshmallow cream for body and on undisturbed cooling for texture. The ingredient list has been scrambled by the book's two-column setting; read it carefully before you begin.

• The garbled ingredient listSet in two columns and run together, it should read: 2 cups sugar, 2 squares chocolate, 1 cup water, 4 tablespoons marshmallow cream, 1 teaspoon vanilla, ½ teaspoon salt. "4 tablespoons marshmallow" and "chocolate cream" are halves of two different lines.
• The hinge: do not stirPouring the hot syrup over the marshmallow cream without stirring, then leaving it alone until lukewarm, is the whole method. Agitating hot sugar syrup seeds large crystals and the fudge turns grainy. Beat only once the pan is comfortable to touch, around 110°F.
• Squares of chocolateA square is 1 ounce of unsweetened baking chocolate, so 2 ounces total. The recipe says grated, which helps cake-form chocolate melt quickly in the syrup; chopped or broken is fine.
• 236°F is not optionalSoft-ball stage sits in a narrow band; a few degrees under gives a fudge that never sets, a few over gives one that crumbles. Use a calibrated candy thermometer rather than the cold-water test, and note that the reading drifts with altitude — subtract roughly 2°F per 1,000 feet above sea level.
• Marshmallow creamThe jarred commercial product of the period, sold under several brand names, is broadly comparable to today's marshmallow fluff or crème. Four tablespoons is a modest amount, enough to interfere with crystal growth rather than to sweeten.
• Boil slowlyExpect roughly 15 to 25 minutes to reach temperature, depending on pan and heat. Wipe stray crystals from the pan sides with a wet brush during the early boil.
• Pans and yieldSomething over a pound of candy. A buttered 8-inch square pan gives a thin slab; a loaf pan gives a thicker one. Mark the squares while the fudge is still soft enough to score but firm enough to hold the lines.