Instructions: Place chocolate and butter in 4- to 6 cup heatproof bowl set in wide skillet of barely simmering water over low heat. Stir frequently until chocolate and butter are completely melted and smooth. Remove bowl and set aside. Leave skillet on low heat.

Place egg yolk in small bowl. Gradually whisk in boiling water.

Place bowl in skillet and stir constantly until yolk mixture thickens slightly to consistency of light cream and registers between 160 and 165 degrees on instant-read thermometer.

Remove from skillet and scrape yolk mixture immediately over melted chocolate. Stir gently, whisking or beating, just until egg is completely incorporated and mixture is smooth. Pour through a fine strainer into clean bowl. Cover and chill until firm, two hours or more.

Remove truffle mixture from refrigerator and allow it to soften about 30 minutes if mixture is very hard. Pour cocoa powder into pie plate. Dip a melon baller or small spoon into glass of hot water, wipe off excess water and scrape across surface of chilled truffle mixture to form a rough, 1 inch ball. Pinch truffle into shape with fingers if necessary - it should not be perfectly round. Deposit truffle into cocoa powder. Repeat with remaining truffle mixture.

Gently shake pie plate to coat truffles with cocoa. Store truffles, tightly covered and refrigerated, up to two weeks or freeze up to three months.

If you would like to email yourself the recipe for later use, or share the recipe with your friends or family, enter the email addresses below and this recipe will be emailed to you and others as well.