Diabetics and others who limit sugar intake often miss out on the simple pleasures of marshmallows -- hot cocoa, smores -- due to the high levels of corn syrup and granulated sugar in a standard marshmallow recipe. Substitutes make marshmallows sugar free so you can enjoy them without guilt or the associated insulin spikes. Aside from the sweetener, sugar-free marshmallows are the same as regular marshmallows, both requiring gelatin to make them semi-solid and egg whites to make them fluffy.
Sprinkle unflavored gelatin powder over cold water in a small mixing bowl. As a general rule, you'll need about 1/2 cup of cold water for every 2 to 3 1-tablespoon packets of gelatin. Add vanilla extract to taste, if desired, using up to 1 teaspoon of vanilla extract for every 1 tablespoon of gelatin. Combine the ingredients well and let rest for a few minutes while the gelatin softens.
Bring water to a boil in a saucepan, using another 1/2 cup of water for every 2 to 3 tablespoons of gelatin powder. Stir in the cold gelatin mixture and cook for a few minutes until the gelatin begins to thicken. Remove the hot gelatin mixture from the heat and set aside to cool. The gelatin thickens as it cools and should reach the consistency of syrup.
Bring your choice of sugar substitute and water to a boil over medium heat, using roughly 1/4 cup of water for every 1 tablespoon of gelatin powder. Continue boiling, stirring constantly, until the syrup reaches soft-ball stage between 247 and 250 F. The amount of sweetener needed depends largely on the type of sugar substitute and your taste preference. You can use a combination of liquid and granular sugar substitutes. For example, you might use 2 cups of granulated sugar substitute for every 2 to 3 tablespoons of gelatin, or substitute one-fourth of the granulated sweetener for a liquid sweetener such as honey, agave syrup or vegetable glycerin.
Mix the sugar syrup into the hot gelatin mixture.
Chill a metal mixing bowl in the freezer for a few minutes. Beat egg whites in the chilled bowl for 3 to 5 minutes or until soft peaks form. If you touch the back of a spoon against the egg whites and lift straight up, the fluffy mixture should lift up with the spoon slightly before curling over and breaking away from the spoon. As a rule, use 1 egg white for every 1 tablespoon of powdered gelatin.
Pour the sweetened gelatin mixture into the egg whites in a steady stream while beating constantly. Continue mixing until the ingredients thicken and become fluffy at firm peak stage. At firm peak stage, the ingredients hold their shape well when you lift a spoon away from the marshmallow mixture.
Dust a baking pan with cornstarch to prevent sticking. Spread the sugar-free marshmallow mixture evenly in the bottom of the pan. Refrigerate for a few minutes until the marshmallows cool and set. Cut the marshmallows into small squares or use small cookie cutters to make playful shapes. Dust all sides of each marshmallow piece with cornstarch to prevent them from sticking together. Store in an air-tight container for up to 1 month.