Makes about 100 1-inch marshmallows
Cornstarch
Confectioners’ sugar
2 cups cold water, divided
3 tablespoons (3 packets) unflavored gelatin
3 cups granulated sugar
1 tablespoon pure vanilla extract
4 tablespoons cocoa powder
2 teaspoons ground cinnamon
Lightly spray a 9-by-13-inch baking pan with nonstick cooking spray and dust with a mixture of equal parts cornstarch and confectioners’ sugar to completely coat the pan.
In a stand mixer fitted with a whisk attachment, place 1 cup of the water. Sprinkle the gelatin on top; set aside to soften the gelatin.
Meanwhile, in a small saucepan, combine the remaining 1 cup of water and the granulated sugar and cook to just past the soft ball stage, about 250°F. When the sugar is at 235°F, add the cocoa powder and cinnamon to the gelatin mixture and mix on the slowest speed. As soon as the sugar mixture reaches 250°F, slowly add it to the gelatin and mix briefly on low, then on high until the marshmallow is thick, glossy and nearly cool, 5 to 7 minutes. Add the vanilla at the end of the mixing time. Spread the mixture evenly into the prepared pan. Allow the marshmallows to sit for four hours uncovered. With a paring knife or pizza wheel dusted with confectioners’ sugar, cut into 1-inch squares.