From the Washington Post. Lots of food writers say homemade marshmallows are amazing.
Ingredients
2 teaspoons vegetable oil, for greasing the pan, divided, plus more as needed
1 1/4 cups (295 milliliters) water, divided
1 ounce (28 grams; 4 packets) unflavored, powdered gelatin
3 cups (600 grams) granulated sugar
1 cup (320 grams) light corn syrup
2 teaspoons vanilla extract or paste
1/4 teaspoon table salt
1 cup (125 grams) confectioners’ sugar, divided, plus more as needed
Instructions
1. Grease a 9-by-13-inch pan with about 1 teaspoon of vegetable oil. Cut a piece of parchment paper long enough to have a generous overhang on the two longer sides of the pan; fit it into the pan and brush with the remaining teaspoon of oil.
2. In the bowl of a stand mixer fitted with a whisk attachment, add 3/4 cup (180 milliliters) of the water. Sprinkle the gelatin into the water and let stand until it dissolves, whisking briefly to ensure all the gelatin is moistened.
3. In a 4-quart saucepan with high sides, combine the remaining water, the sugar and corn syrup. Using a rubber spatula, gently stir to ensure all the sugar is moistened. Use a wet pastry brush or clean wet cloth to wipe the sides of the pan so there are no sugar crystals clinging to it. Attach a candy thermometer to the side of the pan and bring the sugar mixture to a boil over high heat. Cook it, gently swirling the pan occasionally, until the mixture reaches 238 degrees, 6 to 8 minutes.
4. Turn the mixer to medium-low speed and slowly pour the sugar syrup in a steady stream into the gelatin, avoiding the whisk, aiming for the space between the bowl and the whisk. As soon as all of the sugar syrup is incorporated, gradually increase the speed to medium-high, taking care not to raise the speed too quickly, or some of the hot syrup may splash out. Continue beating until the mixture begins to turn white, about 4 minutes. Add the vanilla extract or paste and salt, and increase the speed to high. Whip until the fluff is glossy and quite thick, an additional 4 to 6 minutes.
5. Lightly grease a rubber spatula with oil and use it to transfer the marshmallow mixture to the greased pan, spreading it evenly but quickly, as it will start to set. Cover with a lightly greased sheet of parchment paper. Let the marshmallows cool completely, at least 3 hours and up to overnight, before cutting.
6. To cut: Evenly sift about 1/2 cup of the confectioners’ sugar over a large cutting board. Remove the parchment covering the marshmallows. Lightly grease a chefs’ knife with oil and use it to loosen the marshmallow from the sides of the pan. Using the parchment overhang, pull the marshmallow mass out of the pan and gently invert it onto the confectioners’ sugar. Peel off the parchment and discard. Sift about 1/4 cup of the confectioners’ sugar over the top of the marshmallow. Using the chefs’ knife, greasing lightly between cuts, cut the marshmallow into individual squares. For 24 (two-inch) marshmallows, cut the slab widthwise into 6 strips and lengthwise in 4, or cut as desired. Coat each marshmallow in confectioners’ sugar before serving or storing.