Chocolate Truffle Sauce

3/4 cup whipping cream
2 tablespoons unsalted butter, cut into 2 pieces
12 ounces semisweet chocolate chips or semisweet chocolate, chopped
1 teaspoon vanilla extract
Put the cream and butter in a medium saucepan and heat over medium-low
heat until the cream is hot and the butter is melted. The hot cream
mixture will form tiny bubbles and measure about 175 F on a food thermometer.
Do not let the mixture boil. Remove the pan from the heat. Add the chocolate
and let it melt in the hot cream mixture for about 30 seconds to soften.
Add the vanilla and stir the sauce until it is smooth and all of the chocolate
is melted.
To Freeze: Pour 1 cup of the sauce into each of 2 plastic freezer containers,
leaving 1 inch of space at the top. Loosely cover and cool for 1 hour at
room temperature. Press a piece of plastic wrap onto the top of the sauce
and cover the container tightly. Freeze up to 2 months.
To Serve: Remove from the freezer. Defrost in the covered container
overnight in the refrigerator. Warm the sauce in a medium saucepan over
low heat, stirring frequently. Leftover sauce can be stored up to 2
weeks in the refrigerator.