It just appeared, as if out of nowhere — one day there was no Sardinia Enoteca Ristorante in South Beach, the next day there was. And the day after that the 96-seater was packed to the gills, and hasn't seen an empty chair since. While "party hearty" is the draw for many a SoBe dining establishment, it is Sardi-hearty fare, rustic and robustly flavored, that has lit the fire of the public's fancy here. Lighting the smoky fire of a roaring open hearth are logs of wood beside which you'll find roasting baby suckling pigs, pancetta-wrapped quail, baked baby octopus, peasant-style stews, and Black Angus rib eye steaks. Sardinia offers a surplus of enticements unique to South Beach restaurants, among them olives with wild fennel flowers, boar sausage, chestnut honey, Italy's diverse cheeses, Sardinia's distinctive wines, professional service, and affordable prices — most pastas are $14 to $24; main courses are in the midtwenties range. There are no reservations accepted, so take advantage of a less-crowded lunch hour, or take your place in line.