Create your own marshmallow syrup: In a saucepan, heat 1 cup water and 1 cup sugar until sugar is dissolved. Add 8-10 marshmallows and increase the heat to high, stirring the marshmallows frequently until they're dissolved. Strain into airtight container, let cool and store refrigerated up to 2 weeks. No need to wait the 2 weeks to enjoy SoCo! Try one of our other cocktails below while you wait.