Judy, this is from their web page, in case you don't get the cookbook back in time.
Truffles au Cocolat
Recipe by: Alice Medrich
From: Bittersweet: Recipes and Tales from a Life in Chocolate
1 lb. bittersweet or semisweet chocolate, coarsely chopped*
10 tbsp. unsalted butter, cut into small pieces
2 large egg yolks, at room temperature
½ cup boiling water or freshly brewed hot espresso
½ cup unsweetened cocoa powder (natural or Dutch-process)
Line bottom and sides of an 8x8x2-inch baking pan with parchment paper or foil. Set aside.
Place the chocolate and butter in a medium heatproof bowl in a wide skillet of barely simmering water over low heat. Stir frequently until the chocolate and butter are almost completely melted and smooth. Remove the bowl and stir with a spatula to complete the melting. Set aside. Leave the heat under the skillet on low.
Place the egg yolks in a small heatproof (preferably stainless-steel) bowl and gradually whisk in the boiling water. Place the bowl in the skillet of water and stir constantly with a heatproof spatula, sweeping the bottom of the bowl to prevent the eggs from scrambling, until the mixture registers 160° on an instant-read thermometer, about 3 to 4 minutes. (You will have to remove the bowl from the skillet to take the temperature unless you are agile enough to stir, hold, and read the thermometer at the same time.) For safety, rinse the thermometer stem in the simmering water to sterilize it after each reading. When the yolk mixture is ready, scrape it immediately from the bowl into the melted chocolate. Stir gently (without whisking or beating) until completely blended and smooth. Pour the mixture through a fine-mesh strainer, if necessary, into the lined pan and spread it evenly. Cover and chill until firm, at least 2 hours.
Put the cocoa powder in a medium bowl. Remove the truffle pan from the refrigerator and use the parchment or foil to transfer the truffle sheet to a cutting board. Allow it to soften until you can cut it without it cracking, about 30 minutes if the mixture is very hard. Invert the sheet and peel off the liner. Cut the truffles into 1-inch squares or smaller and toss them in the bowl of cocoa powder. You can leave the truffles square or dust your hands with cocoa and roll truffles into balls. (Store the truffles tightly covered for up to 2 weeks in the refrigerator or freeze for up to 3 months. Remove from the refrigerator about 20 minutes before serving to soften slightly.)
Makes 64 truffles.