And it's easy, too.
In an oblong Corning or Revereware casserole (about 6 x 10 inches) , put 12 ounces semisweet chocolate chips, 1 broken 4 or 6 ounce dark chocolate candy bar (such as Cacao Reserve 67% cocoa), and one stick of unsalted butter (not margarine) cut into pieces.
In a pan over the stove, stir 1 and 1/4 cups half-and-half (or use one 12 ounce can of evaporated milk) with 2 cups of confectioners powdered sugar. Bring to a boil stirring with a wooded spoon or whisk. Boil over medium-high heat for ten minutes. Pour hot mixture over the chocolate and whisk until chocolate is all melted. Add 1/2 teaspoon vanilla extract. Continue to whisk and fold until mixture starts to lose it's shiny texture, about 4 minutes. Add 3/4 cup chopped walnuts or pecans if desired.
Spread mixture evenly in the casserole dish and refrigerate at least 3 hours. Cut into squares.