Makes about 2 dozen truffles
Melt chocolate and butter in the top of a double boiler over low heat, stirring constantly. Remove from heat. Add sugar, egg yolk and almond extract; beat with an electric mixer until smooth. Transfer to a shallow glass casserole dish. Cover and refrigerate 1 hour. Shape mixture into 1 inch balls. Roll in almonds. Cover and refrigerate at least 8 hours. Place in miniature foil cups at room temperature to serve. Store in airtight container in refrigerator.