3 tablespoons unflavored gelatin
⅓ cup room-temperature water
2 cups sugar
½ cup corn syrup
½ cup hot water
2 egg whites (optional)
½ teaspoon salt
1 teaspoon vanilla bean paste or pure vanilla extract
½ cup cornstarch, plus more for dredging
In the bowl of an electric stand mixer fitted with a whisk attachment, add the gelatin and pour the ⅓ cup water over it. Let it rest in the stand mixer (with the whisk in mixing position) until the sugar syrup is ready. Make sure the gelatin is completely saturated with water before you add your sugar syrup.
In a heavy saucepan over medium-low heat, combine the sugar, corn syrup and hot water. Melt the mixture until the sugar has completely dissolved. Raise the heat to medium-high and allow the mixture to boil. With a damp pastry brush, wipe down the sides of the pan to prevent stray sugar crystals from forming. Clip on a candy thermometer and heat to 250 degrees.
Meanwhile, if using egg whites, beat them with the salt until they hold a stiff peak. Because the stand mixer has the gelatin and whisk in it, you will have to beat the egg whites in a separate bowl; a copper bowl and whisk work well, or a stainless steel bowl and whisk, eggbeater or hand mixer. Caution: Any traces of fat in the bowl will deflate the whites, as will using a plastic bowl.
Bring the pot with the hot sugar mixture to the bowl of the stand mixer. Set the mixer speed to medium-low and slowly add the hot sugar mixture, carefully and gently pouring it down the side of the bowl to avoid both splashing and scorching the gelatin (if you heat gelatin at too high a temperature, it loses its efficacy).
Raise the mixer speed to high and beat until the mixture has started to stiffen and has doubled in volume. Add the egg whites, if using, the vanilla and, if you haven't used the egg whites, the salt. Mix until light, white and fluffy.
Cover a sheet pan with aluminum foil and sprinkle with the ½ cup cornstarch, making sure to cover every inch.
For plain, square marshmallows: Spray a plastic spatula with nonstick spray and scoop the entire marshmallow mixture onto the pan. Using an offset spatula, also sprayed, smooth the marshmallow out into an even layer. Work fast -- this stuff stiffens up quickly.
Let the marshmallow dry for at least 4 hours or overnight. Using very sharp knife, a pizza cutter or scissors (each sprayed with nonstick spray), cut the marshmallows into bite-sized pieces. Dredge each piece in cornstarch, making sure each cut edge is covered, otherwise the pieces will stick to anything and everything. You can also use a sharp cookie cutter (sprayed) to make shapes. Dredge in cornstarch.
For curvy marshmallows: Use a pastry bag fitted with a large star tip to pipe shapes onto the prepared pan. Dredge in cornstarch as above.
Store in an airtight container for up to 2 weeks. Marshmallows made without egg whites will last much longer, up to several months.
Makes about 40 marshmallows.
"Sugar Baby" by Gesine Bullock-Prado (2011 Stewart, Tabori & Chang)