Prep: 40 minutes
Cook: 15 minutes
Makes: about 12 large marshmallows
1/4 cup powdered sugar
1/2 cup cornstarch
Pam
2 (1/4-oz) envelopes unflavored gelatin
1 1/2 cups granulated sugar
2/3 cup light corn syrup
6 T cocoa
1/4 cup cocoa
3 T hot water
1. In a small bowl, sift together powdered sugar and cornstarch and 1/4 cup cocoa; set aside. Spray the bottom and sides of an 8" square baking pan with Pam. Cut an 8x12 inch sheet of parchment paper and fit into pan so that it covers bottom and 2 sides. Spray parchment with Pam, and coat parchment and pan with half of the powdered sugar/cornstarch/cocoa mixture. Set aside.
1a. In a small bow, mix together 6 Tablespoons cocoa and 3 Tablespoons hot water until a smooth paste forms; set aside.
2. Fill a large bowl with 1/2 cup cool water and sprinkle with gelatin; set aside. In a medium pot fitted with a candy thermometer, combine granulated sugar, corn syrup, and 1/2 cup water; bring to a boil over high heat. Reduce heat to medium and cook until mixture reaches 240 F., 7-10 minutes. Remove from heat and set aside.
3. Using an electric mixer, beat reserved gelatin mixture on low for about 30 seconds, then pour in reserved sugar: corn syrup mixture in a slow, steady stream down side of bowl. Increase mixer speed to high and beat until very thick, ribbony, and doubled in volume, 12 to 15 minutes.
4. Pour batter into prepared pan. Using dampened fingers, smooth top. Sprinkle remaining powdered sugar/cornstarch/cocoa mixture over top. Let rest, uncovered, in a cool, dry place, about 4 hours or up to overnight.
5. Invert marshmallow onto a dry surface and discard parchment. Using a clean pastry brush, dust excess powdered sugar from the top of the marshmallow onto work surface. Dust a knife in powdered sugar from the work surface, then cut the marshmallow into twelve 1 3/4" squares (you'll have a bit extra). Dip the cut edges in the excess powdered sugar/cornstarch/cocoa mixture on the work surface.