Combine Caramels and Cream in slow cooker and cook on low until melted (30 minutes to 1 hour).
Stir in marshmallows and optional rum and continue cooking on low for 30 min.
Recipe can be prepared in microwave and then kept warm in slow cooker if running low on time. Place caramels and cream in crock and cook on high in microwave for 3 minutes or until caramels begin to melt. Stir and add in marshmallows heating in 30 sec intervals until stirs creamy.This recipe for Crock Pot Caramel Dip is best for a 2-3 qt slow cooker, if you have a bigger model, you may want to double the recipe.