Spaghetti simply dressed with pesto – ‘Spaghetti alla Genovese’ – is delicious enough, but in this refreshingly different variation on the theme the pasta is balanced with sliced new potatoes and extra fine French beans. These slightly surprising additions give a depth and difference to the dish that is quite remarkable and out of all proportion to the simplicity of the ingredients.
Ready-made pesto, sold in small jars, is universally disgusting in our experience and the real thing is very easy to make, as I will describe in a separate post. Or you can simply buy a pot from the shop (coming soon!). Do not be tempted to use more than about one tablespoon per person: it has a very strong flavour and the pasta is just as important as the sauce.
Both vegetables can be prepared well in advance and held: in a large pan of boiling salted water, cook the potatoes until just tender. Refresh in cold water and allow to cool slightly. When cool enough to handle, peel and slice to the same thickness as the beans. Top and tail the beans, cut into 2.5cm / 1in lengths and blanch in well -salted water for 3 minutes. Drain and refresh by dipping briefly in a bowl of iced water to stop the cooking process.
Put as large a pan of lightly salted water to heat as you can for the pasta and remember that it may take 20 minutes to bring such a large pan of water to a fast, rolling boil, so don’t leave this to the last minute. Put a colander in the sink ready to drain the pasta as soon as it is done.
When the pan of water is at a good rolling boil, feed in the pasta by the handful. Never cut or break pasta. The longer it is, the better it tastes. Feed it in slowly, pushing it to coil around the pan as it softens. When it is all under the surface, stir immediately to separate the strands and make sure none sticks to the bottom. Return to the fastest boil you can maintain without the water boiling over .
While the pasta is cooking, put the sliced potatoes , beans and pesto in a warmed serving bowl and mix well. Add some freshly ground pepper to give it an extra lift. Have the bowl standing close to the sink, where the colander is awaiting the spaghetti, and have your tongs ready to toss the ingredients together.
Good-quality dried spaghetti should cook in under 10 minutes, so start tasting after 8 minutes. These days it seems to be smart in Italy to serve pasta not just al dente (tender but still firm to the bite) but nearly raw, something frankly unpleasant. Also remember that it will go on cooking after it is drained.
As soon as you are satisfied that the spaghetti is nearly done, quickly (but carefully) remove from the heat and drain in the colander. Before it is completely drained and while there is still a thin coating of water on each strand (the retained moisture is an important contributor to the texture of the sauce), tip it into the bowl and toss thoroughly with the pesto, potatoes and beans.
Serve at once in large warmed individual bow ls, with large spoons and forks. Torn basil leaves may be added to garnish. You can serve with added Parmesan, but with so much of it in the pesto it hardly seems necessary.