Bring a large covered pot of salted water to boil.
When the pasta water comes to a boil, cook the pasta in the salted water, stirring occasionally, until al dente, tender yet still firm to the bite.
Meanwhile, make the pesto sauce.
Making Pesto with a Mortar & Pestle
Peel the tomatoes: Score an x into the skin of the bottom of each tomato and plunge them into the boiling pasta water for a few seconds. Fish them out and let cool for a minute until cool enough to handle (in ice water if you like). Peel the skins off, push the seed sections out with your thumb (optional), and roughly chop. Set aside.
Pound and grind the garlic, salt and peppercorns into a paste.
Add the almonds a little at a time, and pestle until smooth.
Add the basil leaves, torn up by hand if too big, and pound to a paste.
Add the chopped tomatoes and pestle until smooth.
Blend in the olive oil with a wooden spoon. Taste and adjust for salt.
Making Pesto with a Food Processor or Blender
Cut the tomatoes in half with the skins on, push the seed sections out with your thumb (optional), then cut into quarters. If your tomatoes are large, roughly chop. Set aside.
Blend the garlic, salt, and almonds in food processor, until finely ground to a sandy texture.
Add the basil leaves, tomatoes and olive oil, and blend roughly with short pulses to emulate the rustic texture achieved with mortar and pestle. If you like a smoother paste, blend on high until it looks just right for you. Taste and adjust for salt.
Finish & Serve
Transfer the sauce to a large serving bowl and set aside.
Drain the pasta, reserving 1/2 cup of the pasta water to use if needed, and toss with the pesto. (Optional grated cheese can be added either here, or at the table.) If the sauce seems a little dry, stir in a spoon of pasta water at a time, until creamy.
To serve, sprinkle the pasta, or edge of the plates, with small or torn basil leaves. Serve with coarsely ground pepper and grated cheese at the table. Enjoy! Buon appetito!
Pasta recommendations: Handmade fresh busiate are traditional; Casarecce,gemelli, gnocculi, strozzapreti, fusilli or trofie go very well; any short tubed pasta such as penne or rigatoni; or long pasta such as spaghettoni (thick spaghetti), bucatini (hollow spaghetti); spaghetti, or linguine.