Extraordinary Italian cuisine is waiting for you! If you ask the chef-owner, Riccardo Michi, to name his favorite dishes at Riccardo Trattoria, he answers without hesitation: ''The fish stew viareggina, from my mother's recipe.'' He also grooves on the veal and ricotta meat loaf, cesarina's same source. In 1942 Michi's mamma founded Girarrosto, a traditional Tuscan ristorante in Milan, which won her recognition by Le Cordon Bleu. Her son has learned well: he's quite the master with spaghetti and Manila clams and we figure only Michi and his mother know the secret to Chicago's creamiest panna cotta. Enjoy this certificate for dinner Sunday to Thursday. Value: $100