then grill, flesh sides down, on lightly oiled grill rack (covered only if using gas grill) 4 minutes. Turn fillets over and grill (covered only if using gas grill) until just cooked through, 4 to 6 minutes more.
Sprinkle fillets with some rosemary
Once done, pour or sprinkle with lemon butter sauce
to prepare lemon sauce, heat3 spoon of butter and add lemon juice untill boiled.