At least 1 day in advance: Make drop flowers. Using royal icing and tip 224, pipe 10 rose drop flowers with tip 2 centers for each treat on waxed paper. Let dry overnight.
Bake 1-layer sheet cake. Cut petits fours using smallest round cutter from 101 piece set. Ice lightly in buttercream. Place cakes on cooling grid over drip pan and cover with quick-pour fondant icing. Let dry.
In buttercream, pipe a tip 5 mound. Attach drop flowers to mound. Pipe tip 3 outline stems. Pipe tip 3 bow.