01 -
Place the sweetened condensed milk, chopped chocolate, and butter into a microwave-safe bowl.
02 -
Microwave on medium-high for 30 seconds. Remove from the microwave and stir. Continue to microwave, stirring every 30 seconds, until the chocolate has completely melted and everything is well combined and smooth.
03 -
Pour the sweetened condensed milk into a medium, heavy-bottom saucepan. Add the chopped chocolate and butter.
04 -
Warm over medium-low heat, constantly stirring, until the butter and chocolate are completely melted and the sauce is fully combined. Be careful to never exceed medium-low heat to prevent the sauce from becoming grainy.