3 cups heavy cream
2 tablespoons butter
2 pounds semisweet chocolate, chopped
Scald the cream and butter in a small saucepan over medium heat. Remove from the heat. Place the chocolate in a heatproof bowl. Add the hot cream and let sit for 2 minutes, then whisk until smooth. Let cool to room temperature before using. (The sauce can be kept refrigerated in an airtight container for several days, but it must be returned to room temperature before serving.)