Wash, peel, seed, and chop the tomatoes. Put into a bowl and set aside.
Put the oil and onion into a heavy, broad skillet. Turn the heat to medium or medium-high. Cook until the onion become colored a deep gold.
Add the garlic, stir for a few minutes, turning the heat down, if you feel it might burn.
Add the basil leaves, the anchovy fillet, the lemon juice, and some salt and pepper.
Cook until the juice is evaporated, then add all of the tomatoes, along with any juices, cook at a lively pace for about 7 minutes, maybe 10, correcting for salt and pepper, if necessary.
Meanwhile, boil the pasta, in a copious amount of boiling, salted water, until al dente.
Drain, and toss with the sauce, adding a little extra virgin olive oil, and some pasta cooking water, which you have retrieved, if necessary, to make the sauce a dense and delicious coating consistency.