Insanely delicious chocolate truffles

This recipe comes courtesy my friend Abby, who makes these for Christmas every year. They're pretty damn easy, and will impress the hell out of your friends and family. Seriously, make these. Ok?

Recipe for 4 dozen truffles (or 3 dozen if you make them a bit bulkier)

1 Tb instant coffee, disolved in 1/4 c water (or, 1/3 C espresso)
8 oz semisweet chocolate
1 oz bitter chocolate
3 egg yolks
1/2 c unsalted butter, cut into pieces
1/4 c myers rum or grand marnier
Unsweetened cocoa
Powdered sugar

1 - Chop chocolate into pieces, put in in a double broiler with the coffee, and melt, while stirring.

2 - In a separate bowl, beat egg yolks. Add 1/2 c chocolate mixture to them, beat well, and add back to the chocolate in the pan. Beat well for 2 minutes, let cool for 5 minutes, and then gradually beat in butter, one or two pieces at a time. Make sure no butter is visible, and add the rum/grand marnier.

3 - Refrigerate one and a half hours (or longer if you're making multiple recipes), until firm enough to do the next step.

4 - Scoop up truffles with a teaspoon and drop them onto a cookie sheet. They will be sticky blobs with no particular shape.

6 - Refrigerate for at least half an hour, but probably not more than an hour and a half.

7 - Combine two parts cocoa and one part powered sugar in a lidded container (I like a glass jar). Probably 1/4 c cocoa and 1/8 c powered sugar will be enough. drop truffles into mix, put on lid, shake to coat, and the pluck them out and quickly roll them into a ball with the palms of your hands. Store in a sealed container in the fridge. I also sometimes keep a jar of cocoa/sugar around to freshen them up when needed.