Step 1

Finely chop tentacles. Heat 1/4 cup oil in a wide 5- to 6-quart heavy pot over moderately high heat until hot but not smoking, then sauté tentacles, stirring, until just cooked through, about 1 minute. Transfer with a slotted spoon to a bowl and cool.

Step 2

Stir tomatoes into oil in pot along with basil, sea salt, and 1/4 teaspoon pepper and simmer, uncovered, stirring occasionally, 10 minutes.

Step 3

While sauce simmers, stir together Pecorino, bread crumbs, parsley, garlic, eggs, sautéed tentacles, and remaining 1/4 teaspoon pepper. Gently stuff each squid body with a slightly rounded tablespoon of bread-crumb mixture and pat squid to distribute filling evenly. Weave a wooden pick horizontally across wide opening of each squid to seal. (During cooking, stuffing will expand and squid will shrink, forming a rounded, well-stuffed squid.)

Step 4

Heat remaining 2 tablespoons oil in a 12-inch heavy skillet over moderately high heat until hot but not smoking, then sauté squid, turning over once, until browned and any liquid given off is evaporated, about 6 minutes total. Add squid to tomato sauce and simmer, covered, turning occasionally, until squid is tender, 25 to 30 minutes. Discard picks and serve squid with sauce.