Cracking taste – nut oils

Food critic and cookbook author Rosa Jackson moved to France from Canada in 1995 to work as an interpreter at the Cordon Bleu cooking school. She has since edited five editions of the Time Out Paris Eating and Drinking Guide and written for various publications worldwide. She now divides her time between Paris, where she runs the personalised food itinerary service Edible Paris; and Nice, where she runs the cooking school Les Petits Farcis.

Every cook has a secret weapon. For some, it’s spices; for others, judicious use of sea salt, black peppercorns or chilli pepper. A splash of soy or fish sauce, a squeeze of lemon (or, more intriguingly, lime) juice, a sprig of thyme or a light sprinkling of Parmesan can all lift a dish to a new level. My secret comes in a bottle and has nothing to do with the little green-black fruit so common in these parts. Ever since I discovered Huilerie Leblanc in Paris I have been enamoured with nut oils, which more than any other ingredient bring an unexpected element to the food I eat. They make their way into vinaigrettes, of course, but also add excitement to anything from minimalist braised asparagus to a fragrant Moroccan tagine. More of a hole in the wall than a boutique, with barely room for two people to stand side by side, Huilerie Leblanc is nonetheless a treasure trove of unusual oils. The family has been in the business since 1878, producing walnut oil with its own stone mill. Using the same mill that made their reputation, the Leblancs now press pistachios and pine nuts, almonds and pecans, to name just a few. Each has a distinctive, often powerful, taste and a natural affinity for certain foods, which the English-speaking staff will enthusiastically describe. Nut oils are expensive – though perhaps less so here than at some other specialist shops – and when I can buy only one I make it walnut, the most versatile of them all. Made from toasted nuts harvested in Burgundy and the P�rigord, it happily partners bitter salad greens such as endives, rocket or fris�e, avocado, green beans, beetroot and sharp cheeses like Cantal, roquefort or cheddar (try a salad of very thinly sliced cooked beetroot, shavings of aged Comt� and walnut oil). As with all cold-pressed nut oils I avoid heating it to preserve its properties and flavour, but I might toss it with saut�ed potatoes at the last moment, adding a handful of chopped garlic and flat-leaf parsley. In a salad of more delicate greens I often mix it half-and-half with mild olive oil or neutral-tasting grapeseed oil to temper its strong toasted flavour and make my little bottle last longer. This year I was lucky enough to get my hands on three big bottles of untoasted walnut oil from the Dr�me, a region known for the quality of its walnuts. Extraordinarily fresh-smelling and as fruity as a good olive oil, it has been disappearing at an alarming rate: in salads, it goes beautifully with vinegar made from sherry, Banyuls or any fruit, though it’s equally delicious on its own. Hazelnut oil, with its strong toasted flavour, seems to me too distinctive to use quite so liberally, but I whisk it with sherry vinegar and shallot to drizzle over asparagus (particularly the slightly bitter white variety) or broad beans, or toss it with flinty green Puy lentils, roasted hazelnuts, cider vinegar and fresh mint, an idea borrowed from British chef Yotam Ottolenghi (who also adds celeriac). For a nutty taste, try replacing part of the butter with hazelnut oil in shortbread biscuits, cr�pes or a sponge cake.Lately I can’t get enough of pistachio oil, whose green-gold colour and slightly exotic flavour makes a stunning contrast to snowy white, fresh goat’s cheese. Mixed with fruit vinegar and perhaps thinned with an equal proportion of delicate-tasting olive or grapeseed oil, it makes a beautiful salad dressing whose mysterious taste few people can identify. In summer, my lunch often consists of mesclun, sliced avocado, multicoloured tomatoes, and any combination of nuts, seeds and sprouts in a pistachio dressing. A few drops of this oil transform a simple fish fillet into a luxury dish, and add another dimension to baked apples or pears.An oil that I am just getting to know is huile d’amandon de pruneaux, extracted from the pits of the famed Agen prunes. With a potent scent that reminds me of almond extract, it’s not an oil to use with abandon, but in tiny quantities it makes a remarkable match for Jerusalem artichokes, apple or pear cake and chocolate – as proved by chocolatier Pierre Marcolini, who adds a few drops to his chocolate-covered marshmallows. Whichever oil you choose, be sure to store it in the refrigerator as nut oils turn rancid quickly at room temperature. Not that you will be keeping it for very long.Serves 4I first came across this unusual gaspacho at Le Mirazur, a stunning contemporary restaurant in Menton. It turned out to be easy to recreate at home: the pistachio oil was my own addition.

•  350g (13oz) vine-ripened  tomatoes  •  330g (13 oz) summer  strawberries •  � tsp sea salt (or more,  to taste)•  1 tbsp redcurrant  vinegar or other fruit  vinegar•  A few drops hot sauce•  Pistachio oil•  A few small basil or mint leavesPeel the tomatoes using a serrated peeler or by dipping them in boiling water for a few seconds. Dice roughly. Gently wash the strawberries, then remove their stems. Place the tomatoes and strawberries in a food mill (mouli-l�gumes) or blender and pur�e. If you use the blender, strain the mixture through a sieve. Taste and add a little more tomato or strawberry if necessary to balance the flavour. Season with vinegar, salt and hot sauce. To serve, drizzle with a little pistachio oil and top with small basil or mint leaves.Food critic and cookbook author Rosa Jackson moved to France from Canada in 1995 to work as an interpreter at the Cordon Bleu cooking school. She has since edited five editions of the Time Out Paris Eating and Drinking Guide and written for various publications worldwide. She now divides her time between Paris, where she runs the personalised food itinerary service Edible Paris; and Nice, where she runs the cooking school Les Petits Farcis.