8 ounces bittersweet chocolate finely chopped
1 cup heavy cream
4 tablespoons butter at room temperature cut into 1/4 inch cubes
Place the chocolate in a bowl large enough to hold all of the ingredients. Set aside.
Bring the cream to a full boil in a heavy bottomed saucepan. Remove from the heat and pour over the chocolate. With a spatula stir the cream into the chocolate. Continue to stir without incorporating air bubbles until the chocolate is melted and smooth.
Let cool until 140° on an instant read thermometer. Stir in the butter. When the butter is incorporated the mixture should be smooth and glossy.
Let the mixture cool, stirring occasionally until pipeable.
Use this ganache to fill chocolate macarons or to frost chocolate caramel cake.
Adapted from Chocolate Desserts by Pierre Herme.