in the bottem half of a double broiler, bring water to a boil(enough to be just touching or just below the top pan). turn down heat to medium(sometimes lower, depending on your stove), you want it to just be simmering.
in the top half of the broiler, put chocolate chips, butter, and vanilla; half bury the butter in the chocolate chips.
while chips are melting, grease a 9x9 pan with butter, be generous, it makes it easier to get out.
let the chips melt all the way, a good way to test it is to touch one of the chips in the center of the pan, if it is compleatly melted, the whole pan is.
start stirring the chips, butter and vanilla together, stir as fast as you can.
pour in the can of sweetened cond. milk while continuing to stir (if this is your first time making this, have someone standing by to pour for you).
when well blended add nuts or fruit if desired.
pour into the greased pan.
if you want, you can add stuff to the top, like sprinkles, or crushed up peppermint, whatever sounds good to you.
cover with foil and place in fridge for 24 hours. cut, and eat!!! yummy!