Purple reigns

Add basil to your tomato salad - and, hey pesto!

The first time I met Marco Pierre White was over lunch at his Canteen restaurant, and I ordered the spaghetti with pesto. Feeling slightly daunted by the presence of the omnipotent one, I managed to pick my way through the pesto and leave the spaghetti - at which he looked rather shocked.

But I have long held an affection for pesto's orgy of basil - created by pulverising a heap of tender leaves into a green paste together with the requisite addition of pine nuts, garlic and coarsely grated, pungent cheeses.

In smaller quantities, though, basil can be curiously overwhelming. I have never worked this out, other than to quote the 17th-century herbalist Nicholas Culpeper who wrote that, "basil either makes enemies or gains lovers, but there is no in-between".

A tomato salad or panzanella easily suffers from a few leaves the wrong side of the equation. It becomes harsh and vulgar, affected with the same strains of aniseed and cloves which sing with unrestrained elegance when the leaves are crushed.

These days, even the most conscientious of Italians use a good processor for making their pesto. I have this on the authority of an Italian cook, who also said you should coat the blades with salt to achieve the same result as you would in a pestle and mortar. "Trrrry it, trry it," she huskily insisted, in a manner that left me in no doubt she was right.

This brings us to the business of chopping or tearing - an issue that has travelled through the ages, first with lettuce leaves, and now with the more delicate subject of how best to provide the finest fragrance of basil for your plum tomatoes on the vine.

I am relieved that Harold McGee has done most of the work for me on this in his The Curious Cook - Taking the Lid Off Kitchen Facts and Fallacies. Having always lived by the rule of the knife, I was interested to delve further into the subject.

"Tearing divides a leaf along the boundaries between cells," says McGee in a chapter entitled The Green and the Brown, "while a knife cuts right through cells. So tearing does less damage to the leaf than cutting, and, therefore, prolongs its fresh appearance."

Like all the best scientific experiments, he takes us through method, results and conclusion. Method: he takes some basil, which is prone to browning at the best of times, and tears it. Result: while the cut pieces develop a brown edge, the torn edges stay green. Conclusion: for a tomato salad to stay looking good, you should tear rather than cut your herb.

But enough of science and more of gustatory pleasure. It is a delight to find opal basil in pots beside the common green Genovese variety. I have always loved the sweeter fragrance of the purple one. In fact, it is my first choice in salads. It looks completely different with smaller leaves splayed at the edges.

I tasted my way through some of the other varieties when I visited the Fetzer Food and Wine Center in California, and there are strange and wonderful differences between them. Gently rub the leaves of the "cinnamon basil" and its scent is true to its name, while the "lettuce-leafed basil" has vast, floppy leaves that are large enough to wrap around a scallop and throw on the grill.

For pesto, though, the "Genovese" is made for the job. Freshly picked and consigned to the blade when its fragrance has the clarity of a garden after rain, it's easy enough to forget to eat the spaghetti.

Summer vegetables with pesto, serves 4

What Mr McGee omits to say in his treatise on basil and pesto is that spaghetti is not the only partner for this glorious, smudgy green sauce. I can happily spread it on a wide variety of things.

Pesto:

40g/112oz basil leaves

15g/12oz pine nuts

1 small garlic clove

4 tbsp extra virgin olive oil

25g/1oz freshly grated Parmesan

sea salt and black pepper

To make the pesto, place the basil, pine nuts, garlic and olive oil in a food processor. Reduce it to a puree, incorporate the cheese and season. Cover and chill. If you do need to keep it, then cover the surface with a fine layer of olive oil.

Vegetables:

700g/1lb 8oz largish new potatoes

50g/2oz unsalted butter

1 lemon

sea salt

175g/6oz fine French beans, topped and tailed

150g/5oz shelled fresh peas

caster sugar

Preheat the oven to 180C (fan oven)/190C (electric oven)/375F/Gas 5. Peel the potatoes and cut them into match sticks about 0.5cm/a quarter of an inch thick. Rinse and drain thoroughly. Place on a piece of foil large enough to enclose them. Dot with the butter, reserving a knob for the peas, and with a smidgen of lemon zest, squeeze over a little lemon juice and season with salt. Fold up into an airtight package and bake for 50-60 minutes.

When the potatoes are nearly cooked, bring a large pan of salted water to the boil and cook the beans for 3-5 minutes until just tender, then drain.

To cook the peas, place them in a saucepan with 3tbsp water, a large pinch of sugar and salt and a knob of butter and cook for about 3 minutes, tossing them.

Combine all the vegetables in a bowl and toss with the pesto. Serve straightaway