Usually I go into a brief spell of mourning when a chef I admire leaves a restaurant. But when Robbin Haas left Bex (561 E. Palmetto Park Rd., Boca Raton, 561-391-0000) for Red Square (an eatery in South Beach) four weeks ago, I wasn't as upset as I thought I'd be. Not because I don't appreciate Haas' work with Asian flavors, but because his replacement happens to be another of my local favorites. New executive chef Doug Riess, who worked for nine years as Mark Militello's executive chef at Mark's Place in North Miami and then manned the stoves at Grove Isle in Coconut Grove (formerly Mark's in the Grove), has taken the reins. "Robbin was Pacific Rim," Riess said recently. "I like Asian flavors as well, but I'm a bit more Caribbean, with a touch of Mediterranean thrown in." Riess' new menu includes grilled Bahamian conch with jicama salad and lime-chili sauce for an appetizer; goat cheese-crusted Australian lamb loin with root vegetable mash and Provence olive sauce for a main course; and tropical tiramisu for dessert. "My goal," Riess said, "is to make Bex one of the top 100 restaurants in the nation." With ambition like that, who's got the time -- or the inclination -- to grieve?