"If there's no chocolate in Heaven.....I'm not going."
3 cups heavy cream
1 1/2 pounds bittersweet, not unsweetened chocolate, chopped
Bring cream to a simmer in a heavy saucepan, then remove from heat. Whisk in chocolate until melted and smooth. Transfer to a metal bowl, cover, and chill--stirring occasionally--until chocolate is thick enough to spread, about 3 to 4 hours. If chocolate gets too hard, you'll have to melt it, and chill again.
Makes enough to fill and frost a 9" cake.