Place a small saucepan over medium heat and melt the butter.
4 T unsalted butter
Add the brown sugar and stir to combine.
1/2 cup dark brown sugar
Add the cream and stir until fully combined.
1/2 cup heavy cream
Bring mixture to a low boil/simmer and cook for about 6-7 minutes, stirring occasionally.
Remove from heat and whisk in 3 teaspoons of miso paste and the vanilla. Taste and add the last teaspoon of miso if desired (I like mine with 4 teaspoons but it's pretty salty... which is great!)
4 t white miso paste, 1 t vanilla extract
Serve over ice cream, dip fruit in it, eat it straight, drizzle it on cake... the possibilities are endless.
Store the leftovers in an airtight container in the fridge, and reheat before using.