Puy lentils are small, slate-grey or greeny blue in colour, with a rich peppery taste. They take their name, Lentilles du Puy, from Le Puy, the area in France where they are cultivated. They are also sometimes sold as lentilles vertes. This is a trifle confusing because they are quite different from Continental lentils which are also often called green lentils. To add to the confusion, these same ‘green' lentils come in various other colours, notably brown and grey.
Still, as far as cooking is concerned, Puy lentils are unmistakably themselves. If you like them, you'll really like them, so it's sensible to cook more than you need for the pâté and keep the rest for something else. They are one of the few pulses adored by non-vegetarians as well as vegetarians, and feature in a number of classic French dishes. They are marvellous in stews, sauces, and soups, and once cooked they will keep well in the fridge for several days.
I would advise soaking the lentils in cold water for three or four hours. This is not strictly necessary, but it should reduce the cooking time to about thirty minutes, or even less. Cover well, bring to the boil, then simmer gently, spooning off any scum that comes to the surface during cooking. Drain. Reserve the cooking water.
This pâté is notably simple and pure, with the two main ingredients being allowed to release their natural strong flavours and blend distinctively together. Even so, onion and/or garlic would do well here, so if you wish to use them, start by frying them together with the mushroom, then follow the rest of the recipe
Puy lentils, 225g (8oz) cooked weight, or the contents of a 400g tin, drained and rinsed
Juniper berries, 20 or so lightly crushed, most conveniently in a pestle and mortar
1 large field mushroom, peeled and chopped
Stock, using the lentil cooking water and one stock cube or stock pot
Yeast extract, about a quarter of a level teaspoon
Salt and pepper
Fry the mushroom gently in oil or fat. Stir in the puy lentils and juniper berries and cook for another couple of minutes. Add a little salt and pepper and the stock. Bring to the boil and simmer, with the saucepan uncovered, until there is virtually no liquid left. This should take about ten minutes.
Leave to cool slightly and blend. If the blades stick, you may need to add a little more stock to the mixture, but be careful not to use too much. You want the final texture to be spreadable but firm. Pot and chill in the fridge. Freezes well.