Make 5-petal flowers 1 day in advance. Prepare royal icing following recipe directions. Divide icing in half. Tint half of icing violet and the other half blue. Cover flower nail with icing flower square. Use tip 102 and violet or blue icing to pipe 5-petal flowers. Use tip 3, cut disposable bag with coupler and matching color icing to pipe dot centers. Let dry 24 hours on waxed paper-covered surface. Reserve remaining royal icing.
Make cookies. Prepare and roll out dough following recipe directions. Use circle metal cutter to cut cookies. Bake and cool cookies.
Decorate cookies. Prepare buttercream icing following recipe directions. Use 9 in. fondant roller with purple guide rings to roll out fondant 1/8 in. thick. Use circle metal cutter to cut fondant circles. Use spatula and buttercream icing to ice cookies. Position fondant circle on cookie. Use straight side of second largest (2 3/8 in.) blossom cut-out from set to imprint flower shape on fondant circle. Use tip 2, cut disposable decorating bag and thinned violet or blue royal icing to outline two petals at a time. Use brush to make brush embroidery design. Repeat until all petals are piped and brushed. Let dry. Use tip 2, cut disposable bag and thinned violet or blue royal icing to attach 5-petal flower to cookie.