200g good-quality dark chocolate, broken into squares
1 t vanilla extract
2 T butter
1/4 cup brown sugar
Melt chocolate pieces in large stainless steel mixing bowl (or top of double boiler) over saucepan of gently simmering water. Be sure water does not touch bottom of mixing bowl to prevent chocolate from burning. Add the rest of the ingredients and whisk. Boil hot fudge for few minutes to reduce to consistency you desire. It should be quite thick and shiny. Cool slightly and serve over sundae.
Image: "Chocolate Sauce" by xXInvaderxGirXx