Homemade Chocolate Marshmallows
1 1/2 cups granulated sugar
1 cup light corn syrup
1/4 teaspoon salt
1/2 cup water
3 envelopes unflavored gelatin
2 teaspoons pure vanilla extract
2 tablespoons cocoa powder
Confectioners' sugar, as needed for dusting
Lightly oil a 9 x 9 square nonmetal baking dish. With a sieve, generously dust the dish with confectioners’ sugar and set aside.
Combine the sugar, corn syrup, salt and 1/2 cup water in a small saucepan and heat over medium heat until the sugar dissolves.
Raise the heat to high and cook until the sugar syrup reaches 240 degrees on a candy thermometer. Note, be sure to handle the syrup carefully, as sugar burns are very painful. Remove from the heat.
Working quickly, so your syrup does not cool and harden, combine the gelatin and 1/2 cup cold water in the bowl of an electric mixer, such as a KitchenAide, fitted with a whisk attachment.
With the mixer on low-speed, slowly pour the sugar syrup into the dissolved gelatin. Add the cocoa powder.
Put the mixer on high and whip until the mixture is very thick and fluffy, about 15 minutes.
Add the vanilla and mix thoroughly to incorporate.
Pour the marshmallow mixture into the prepared pan. The mixture will be sticky and elastic and somewhat tricky to smooth out. I suggest wetting your fingertips with water and gently pressing the mixture evenly into the pan.
Dust the top with more confectioners’ sugar and allow to stand uncovered for 8 hours or overnight, until it dries out.
Turn the marshmallow onto a cutting board. Using a long knife, cut into squares or other desired shapes. Sprinkle your knife with confectioners’ sugar in-between cuts to prevent the marshmallows from sticking.
When done cutting, dust all the pieces with confectioners’ sugar to prevent them from sticking together.
Stored between parchment paper, in an airtight container, in a dry cool place, the marshmallows should keep for about one week.