Recipe
Ingredients
Vegetable oil (for brushing sides of pan)
4 envelopes of unflavored gelatin (This equals 3 Tablespoons + 1 ½ teaspoons)
3 cups granulated sugar
1 ¼ cups light corn syrup
¼ teaspoon salt
2 teaspoons pure vanilla extract
1 ½ cups confectioners' sugar
Directions
Lightly brush a 9-by-13-inch baking dish with oil—dust with ½ cup of powdered sugar (make sure the sides are coated); set aside.
Put 3/4 cup cold water into the stand mixer bowl; sprinkle with gelatin. Set aside, let soften for 5 minutes.
Put granulated sugar, corn syrup, salt, and 3/4 cup water into a medium saucepan. Stir once and bring to a boil over high heat, stirring to dissolve sugar. Cook, without stirring, until mixture registers 238 degrees on a candy thermometer (about 9 minutes).
Pour the Sugar mixture into a liquid measuring cup
Attach the stand mixer bowl with gelatin to the stand mixer (fitted with the whisk attachment). With the mixer on low speed, beat the hot syrup into the gelatin mixture. Gradually increase speed to high; beat until mixture is very stiff, about 12 minutes.
Beat in vanilla on low speed. Pour into the prepared dish, and smooth with a rubber spatula.
Dust the top of the marshmallows with ½ cup of sifted powdered sugar
Set aside, uncovered, until firm, about 3 hours, or overnight
Sift an extra 1 cup confectioners' sugar onto a work surface. Unmold the marshmallow onto confectioners' sugar. Lightly brush a sharp knife with oil, then cut the marshmallow into 2-inch squares. Sift the remaining 1/2 cup of powdered sugar into a small bowl, and roll each marshmallow in the sugar to coat. Marshmallows can be stored in an airtight container up to 3 weeks.