This courage of conviction allows such friends of the designer as Caroline Issa and Brazilian princess Paola Orléans e Bragança and other fans—like, say, Gwyneth Paltrow—to stand tall in her designs. (The five-inch pumps she collaborated on with Manolo Blahnik also help).

Casasola has a Central Saint Martins degree and design work at Lanvin on her résumé, but she says she learned the most from her seamstress grandmother, who never left the house in anything but a maxi-length. The lesson, she says: “Luxury is simplicity.”