Ingredients

1/2 cup heavy cream 

3 1/2 ounces dark chocolate, finely chopped (preferably 70 percent cacao) 

1/2 ounce (1 tablespoon) unsalted butter, softened 

Preparation

Bring cream to a boil in a saucepan over medium-high heat. Pour cream over chocolate in a heatproof bowl. Let stand for 2 minutes. Add butter, then whisk mixture until smooth. Let cool, stirring often. Use immediately.