I make brownies for my christmas party, along with a dozen or so other deserts. These are very fancy and go over really well.
The recipe i referred to is Julia Child's frosting for reine de saba, i think. I do it just by eye.
Take equal parts (or a little more chocolate than butter) of semisweet chocolate and butter
Melt chocolatre in a double boiler, remove from over the water. Add butter in slices and mix in till melted, and by the end you should have a substance like mayonnaise.
If it's too hard, mix over warm water a minute, and if too soft, put it over ice water.
Spread over the brownies. If you want you can strew sliced almonds over it and they will stick if you've just spread the frosting.
I cut into diamonds, which are much more appealing for some reason. And I cut them small because they are so rich,.
Some people will eat one of these (and then often another and more) but wouldn't venture to take a large one.
(I think i had posted this already but it didn't show up for some reason)