Make shamrocks 2 to 3 hours in advance. Tint five 1 3/8 in. balls of fondant five shades of green, from light to dark. This will make two shamrocks and a fondant strip in each color. For each color shamrock, roll three ¼ in. balls. Cut three of the balls in half. Roll each half into a cone shape. Use damp brush to attach two cones, pointed ends together, to form each leaf. Flatten slightly. Repeat for a total of three leaves on each shamrock. For stem, roll a log, 3/8 in. long x 1/16 in. dia. Use damp brush to attach leaves to log. Trim log, leaving about 3/16 in. exposed. Let dry on cornstarch-dusted surface, about 2 to 3 hours.