Pastry chef Thoa Nguyen dreamed of running her own Parisian-style, Asian-fusion bakery for years. One of the daughters of the former owners of New Saigon, she grew up in the restaurant business. Now she’s running the show at this spot, which excels not only in such sweets as crepe cakes and croissants, but savory options like banh mi and classic Parisian-style ham and butter sandwiches.