Empty sweetened condensed milk into a wide mouth Mason jar. Put on lid and band and place in slow cooker. Fill with water to just above the line of the milk on the jar. Cook on low for 4 to 5 hours until milk has darkened and thickened.

Dip marshmallows into the sauce. You can either use a toothpick or use a fork. Scrape the excess sauce off on the lip of the jar with the bottom of the fork. Put on waxed paper. Place in the freezer for 30 minutes.

Melt chocolate chips over a double broiler or in the microwave just until shiny. Stir until just combined. Add coconut oil. The heat from the chocolate chips will melt the oil. Before chocolate sauce cools, quickly dip caramel covered marshmallows in the chocolate. Sprinkle with sea salt.

Place in the freezer for 20 minutes or the fridge for an hour. Try not to inhale entire pan in one sitting.