Homemade Marshmallows

In a bowl, sift together 1/2 cup (2 oz./56 g) of the confectioners’ sugar and 1/2 cup (2 oz./56 g) of the cornstarch.

Butter the bottom and sides of a 9-by-13-inch (23-by-33-cm) baking dish with the 1 Tbs. butter. Sift about half of the confectioners’ sugar–cornstarch mixture over the butter to evenly coat the bottom and sides. Tap out any excess. Reserve the remaining half of the mixture.

In the bowl of an electric mixer, combine 1/2 cup (4 fl. oz./125 ml) of the water and the gelatin and stir just until combined. Let stand until set, about 10 minutes.

Meanwhile, in a small saucepan over medium heat, combine the remaining 1/2 cup (4 fl. oz./125 ml) water and the granulated sugar. Heat, stirring, just until the sugar has dissolved, then cook, without stirring, until the syrup registers 240°F (115°C) on a candy thermometer, 5 to 10 minutes.

Fit the mixer with the whisk attachment and beat the gelatin mixture on low speed to break it up. With the mixer running, slowly and carefully add the hot syrup in a continuous stream. When the gelatin and syrup are fully combined, increase the speed to high and whip until the mixture has tripled in volume and soft peaks form, 8 to 10 minutes. Set aside.

In a separate mixing bowl or in a clean bowl of a stand mixer, combine the egg whites and salt. Using a handheld mixer or a stand mixer fitted with a clean whisk attachment, whip the egg whites on medium speed until foamy, about 1 minute. Add the cream of tartar, increase the speed to medium-high and whip until stiff peaks form, about 3 minutes. Using a rubber spatula, gently fold the egg whites and the vanilla paste into the gelatin mixture until just combined. Be careful not to overmix.

Gently spoon the marshmallow mixture into the prepared baking dish and spread evenly. Sift the reserved confectioners’ sugar–cornstarch mixture over the marshmallow. Let set overnight, uncovered, at room temperature.

When the marshmallow is set, sift together the remaining 1/4 cup (1 oz./28 g) confectioners’ sugar and 1/4 cup (1 oz./28 g) cornstarch onto a clean work surface. Run an offset spatula around the edges of the dish and turn the marshmallow out onto the surface. Lightly grease a sharp knife or a cookie cutter, which helps ensure a clean cut, then cut the marshmallow into the desired shapes and sizes.

Coat the marshmallows on all sides with the confectioners’ sugar–cornstarch mixture, shaking off any excess. The marshmallows can be stored in an airtight container at room temperature for up to 1 week. Makes about 24 marshmallows.

Williams Sonoma Test Kitchen