- ½ cup confectioners' sugar, plus additional for sprinkling if desired
- 3 envelopes unflavored gelatin (about 3 tablespoons)
- 2 cups granulated sugar
- ¼ cup mild, light-colored honey such as orange blossom or clover
- 2 large farm-fresh egg whites
- ¼ teaspoon kosher salt
- 1 tablespoon vanilla extract
- Line a 9-by-13-inch baking dish with foil, smoothing the foil into the dish so there are no wrinkles to leave an unsightly pattern on the marshmallows. Sift ¼ cup of confectioners' sugar into the bottom of the dish.
- Place the gelatin in 1 cup cold water to bloom. Place a candy thermometer in a saucepan over a medium heat; cook the granulated sugar, honey, and ½ cup water, stirring until the sugar dissolves, until the mixture reaches 240 degrees.
- In the bowl of an electric mixer, whisk the egg whites and salt until soft peaks form. When the sugar mixture has come up to temperature, carefully pour it into the egg whites while whisking. Continue whisking until the mixture has cooled slightly, about 1 minute, then add the gelatin mixture and the vanilla. Continue whisking until the mixture begins to thicken and quadruples in volume, 5 to 7 minutes. Scrape the marshmallow into the prepared pan and smooth the top with a spatula. Sift the remaining ¼ cup confectioners' sugar on top. Allow the marshmallows to set for 4 hours or overnight. Cut them into 2-inch squares and store in an airtight container in the refrigerator or at room temperature. The marshmallows will keep for 2 to 3 days at room temperature, and up to 1 week if chilled.
- Sprinkle with additional confectioners' sugar before serving, if desired.