1. Cook sugar, corn syrup, water and xanthan gum in 4 quart sauce pot. Stirring often, and brushing sides with water using pastry brush to prevent sugar crystals from forming. Cook sugar mixture to 240°f. Pull off range.
Beating Marshmallow Creme
2. When cooked sugar reaches 230°f start beating egg whites in stand mixer with whisk attachment on high speed. At the point of eggs white reach foamy stage add cream of tarter. Continue beating to soft peak stage.
3. Add cooked 240°f sugar in steady stream while egg whites are beating on high speed. Continue beating on high speed for 5 minutes until marshmallow creme constancy is achieved.
4. Store the marshmallow creme in pint or quart mason jars. Secure with lid and ring, label and date each jar.
The marshmallow creme is good for months refrigerated.