Spare Spoons Kitchen
Made up one night from what was in the house: two anchovies melted into olive oil, a sliced shallot softened for a few minutes, then cherry tomatoes blistered right alongside it, half of them mashed into a sauce. A pat of butter pulls it together. It's done by the time the pasta is.
Get these into the state the recipe asks for first — the steps that use them won't wait.
Scared of anchovies? Try it anyway. Nobody is asking you to put a whole anchovy in your mouth. The fillets go into warm oil and dissolve completely in a couple of minutes, and by the time the tomatoes are in there is nothing left to see or pick out. What stays behind is savory depth, the same thing Parmigiano or a splash of Worcestershire sauce adds (and Worcestershire is made with anchovies, as is a good Caesar dressing). Most people who say they hate anchovies have only met them whole, bony and very salty on top of a pizza. Melted like this, they don't taste of fish. They make you wonder why the sauce tastes so good. If you really can't, the garlic swap below makes a different but very good version.
Slice, don't mince. A sliced shallot is the fastest knife job in the recipe, and the thin half-rings turn into sweet, soft ribbons that sit in the sauce. Giving them just a head start before the tomatoes go in means they soften in the juices instead of frying, so they never get crisp or bitter.
Spaghetto Quadrato. La Molisana's square-cut spaghetti (No. 1, sold in half-kilo bags; Italian delis, Central Market, Amazon) has a square cross-section instead of a round one. The corners give it a chewier bite, and the flat sides hold a thin sauce like this one especially well. Plain spaghetti or linguine is just as good.
Why no cheese? I leave it off on purpose. The anchovies already do what cheese usually does in a pasta like this, salt and savory depth, and the butter brings the richness. Parmigiano on top dulls the fresh, sweet-sour taste of the tomatoes, and it fights the lemon. If you want something on top, toasted breadcrumbs (pangrattato, sometimes called poor man's Parmesan) add crunch without covering anything up.
Salt goes last. Between the anchovies and the salted pasta water, the sauce may need no added salt at all. Taste after the pasta is tossed in, not before.
The rest of the tin. Move leftover fillets into a small jar, cover them with olive oil, and refrigerate. As long as they stay submerged they keep for weeks, ready for the next time.
No anchovies, or vegetarian: use garlic instead, one thinly sliced clove per anchovy fillet, cooked gently in the warm oil until pale gold before the shallot goes in. It makes a different sauce, but a very good one. For more of the anchovies' savory depth, also stir a teaspoon of white miso into the oil.
Vegan: the garlic (and miso) swap above, plus an extra splash of olive oil in place of the butter at the end.
Gluten-free: Barilla Gluten Free Spaghetti (blue box, pasta aisle). Pull it a minute early and save the cooking water as usual.
No shallot: the same weight of red onion, sliced thin, works the same way. Give it an extra minute on its own before the tomatoes go in.