Place the lobsters in the freezer about 30 minutes before beginning this recipe. (This will make it easier to take them apart.)

Bring a large pot of salted water to a boil over high heat for the pasta.

Remove the lobsters from the freezer, and start by cutting off their claws and legs with a sturdy pair of kitchen shears. Whack the claws with a meat mallet just hard enough to crack the shells, and use the shears to cut along one side of the joints attached to the claws. (Cracking the claws and cutting the joints will make it easier to remove the meat from the shell after the lobster is cooked.)

Lay each lobster on a cutting board with the tail stretched out, and cut in half lengthwise by inserting a heavy, sharp knife where the tail meets the head section. Holding the tail firmly as you cut, bring the knife down to the cutting board in a swift motion, cutting the body cleanly in half. Turn the knife in the other direction and cut the tail in half in the same way. Open up the cut lobster, and remove the antennae and eyes with the shears, making sure to scrape out the digestive sac located inside the shell behind the eyes. Pull out the dark vein that runs along the tail, but leave the tomalley—the pale green mass in the head close to the tail—intact. (It adds wonderful flavor to the sauce.)

Heat 1 cup of the vegetable oil in a wide, heavy skillet over medium heat. Dredge the meat side of the bodies in flour, patting lightly with fingers so it will adhere to the lobster. When the skillet of oil is hot, add the floured lobster quarters cut side down, continue adding as many as will fit comfortably in the skillet. Cook until the lobster meat is lightly browned, about 5 or 6 minutes. Remove from the pan, and repeat with the remaining lobster pieces, if necessary, adding more vegetable oil to the pan as needed. When all the lobster bodies have been lightly browned, add the claws to the pan and cook, turning them with tongs, until the shells turn bright red on all sides, about 4 minutes. (Turn the lobster pieces carefully—they are likely to splatter.)

Heat the olive oil in a wide, deep braising pan large enough to hold all the lobster pieces, over medium heat. Whack the garlic cloves with the side of a knife, and add them, along with the small lobster legs, to the oil. Cook, shaking the pan, until the garlic is lightly browned, about 3 minutes. Pour in the crushed tomatoes; add the peppers and dried oregano, and season lightly with salt. Bring the sauce to a boil, and adjust the heat to a lively simmer for 10 minutes.

Meanwhile, stir the spaghetti into the boiling water. Cook, stirring frequently, until done, about 6 minutes.

Stir in the fresh oregano and tuck all the lobster pieces into the sauce skillet. Cook at a lively simmer just until the lobster meat is cooked through and juicy, about 5 minutes. If the sauce becomes too dense as it simmers, ladle a little of the pasta-cooking water into the pan. Keep the sauce and lobster warm over very low heat.

Drain the spaghetti, and return it to the empty pot. With a ladle, spoon the liquid portion of the lobster sauce over the pasta, leaving just enough sauce behind in the pan to keep the lobster pieces moist. Bring the sauce and pasta to a boil, stirring gently to coat the pasta with sauce. Check the seasoning, adding salt if necessary.

Divide the dressed spaghetti among six pasta bowls. Top each with half a lobster body, tail, and one claw. Spoon some of the sauce remaining in the pan over each serving, and serve immediately.