1 Put the chocolate chips in a large heatproof bowl. Bring the cream to a boil in a medium saucepan. 2 Just before the cream comes to a full boil, pour the cream into the chocolate chips and whisk together until smooth. 3 Add the butter and stir until smooth and shiny. Place plastic wrap directly over the surface to prevent a skin from forming, then let stand at room temperature overnight to cool. Store in the refrigerator, covered, for up to three weeks.