Pour 10 cups (2.4L) water in the basin of the Wolf Steamer. Heat to 140ºF (60°C), covered with steamer lid. In solid basket, place chocolate chips, butter, water and liqueur. Place basket in steamer. Heat about 10 minutes or until chocolate and butter is melted, stirring occasionally. Remove pan from steamer and gently whisk in egg yolk until just combined. Place pan in Sub-Zero refrigerator for 1 hour or until firm. (Do not refrigerate overnight.) When chilled, scoop chocolate by tablespoon and roll each into a ball. Roll balls into cocoa. Place balls on waxed paper lined baking sheet. Repeat until all mixture is used. Refrigerate until firm. Store in refrigerator.
Wolf Electric or Induction Cooktop:
In 2-quart saucepan on MELT, place chips, butter and water. Heat about 20 minutes or until melted, stirring occasionally. Remove from heat. Gently whisk egg yolk and liqueur into mixture. Place pan in Sub-Zero refrigerator for 1 hour. (Do not refrigerate overnight.) Continue as above.