(01/09/2011: Edited to clarify a few points)
I am told this is a Martha recipe. It’s fun to do! Make sure your kitchen workplace is spotless. This recipe makes about 2 dozen large marshmallows, which should be eaten within a week.
You need a candy thermometer for rather exacting measurements (you’ll be cooking the mixture to “soft ball” stage) and a really rugged mixer – a Kitchenaid at minimum. I one broke a Hamilton Beach on these suckers.
1 1/2 cups cold water, divided
4 envelopes unflavored gelatin (about 3 1/3 Tablespoons)
3 cups granulated sugar
1 1/4 cups light corn syrup
1/4 teaspoon salt
2 teaspoons pure vanilla extract
1 cup powdered sugar
1. Brush a 9 by 13 inch Pyrex baking dish with vegetable oil. Set aside.
2. Pour 3/4 cup water in the bowl of an electric mixer, sprinkle with gelatin; let stand and the gelatin will soften.
3. Place the granulated sugar, corn syrup, salt, and remaining 3/4 cup water in a medium saucepan; bring to a boil over high heat. Clip a candy thermometer to side of pan; cook until mixture reaches the soft-ball stage, 238 to 240 degrees. Remove from heat.
4. With mixer on low speed, using whisk attachment, add hot syrup to gelatin mixture, pouring down the side of the bowl to prevent splattering. Gradually increase speed to high; continue beating until mixture is cool and stiff peaks form, about 30 minutes. At first the mixture will be an ugly yellowish slurry, but soon it begins to transform. Just before it gets rather sticky, beat in the vanilla.
5. Pour mixture into prepared baking dish; smooth top with an offset spatula. Let stand, uncovered, at room temperature until firm, at least 3 hours or overnight.
6. Sift 1/2 cup confectioners sugar onto a clean work surface. Invert baking dish onto sugar, and lift to remove. (This part can be tricky – be patient and use a broad flat implement lightly oiled to help pry out the mass). Lightly oil a sharp knife and cut marshmallows into 2 inch squares. Sift remaining 1/2 cup confectioners sugar into a bowl and roll marshmallows in sugar to coat evenly.
7. Store marshmallows in an airtight container at room temperature for up to a week.