Voluptuous fresh cattleya orchids spill over a white fondant-covered cake. Use only pesticide-free blooms, and the flowers should be removed before serving.
Cover tiers: Thinly coat each tier with desired frosting; refrigerate to set. On a clean work surface lightly dusted with cornstarch, roll enough fondant to cover respective tiers (see fondant amounts, above; work with one tier at a time). The fondant should be rolled into a large oval approximately 1/8 inch thick. Working quickly, lift fondant, center it over tier, and gently lay it on cake. Starting from the center, smooth it onto cake with your hands. Trim excess fondant from bottom edges using a pizza wheel. (Excess may be reused if it is free of crumbs, filling, or icing.) Repeat, covering all tiers. Covered tiers do not need to be refrigerated unless filling must be chilled.
Stack tiers: Center and place largest tier on silver tray. (Use an 8-by-6-inch rubber rug mat to keep it from slipping.) Insert ten dowels in an oval 3 inches from edge, and four more within oval. Smear a tablespoon of royal icing over top of tier; center and place 13-by-9 3/4-inch tier on top. Insert six dowels in an oval 2 1/2 inches from edge, and two more within oval. Smear a tablespoon of icing over top of tier; center and place 10 3/4-by-7 7/8-inch tier on top. Insert remaining four dowels in an oval 2 1/4 inches from edge. Smear a tablespoon of icing over top of tier; center smallest tier on top.
Pipe and paint borders: Fit a 12-inch pastry bag with an Ateco number 349 diamond tip, and fill halfway with royal icing. Pipe a border around lower edge of each tier; let icing dry, about 30 minutes. Mix 1/2 teaspoon pearl dust with 1 teaspoon lemon extract; using a small paint brush, paint borders this color.
Decorate tiers: Just before decorating, clip the blooms with about 2 inches of stem. Bend the 2-inch-long pieces of white florists' wire into a U shape, like a hairpin. Place each flower on cake where you want it to be attached, and slide hairpin over the stem and into cake.
Fondant Amounts (Approximate): For the 7 3/4-by-5 3/4-inch tier, 2 pounds; 10 3/4-by-7 7/8-inch tier, 3 pounds; 13-by-9 3/4-inch tier, 4 pounds; 16-by-12 3/4-inch tier, 6 pounds.