How to make the perfect lentil soup – recipe

Many cultures have a lentil soup as part of their culinary repertoire – the comforting way they thicken and enrich a broth has endeared them to cooks from Colombo to Casablanca, and farther afield, too. The local version below has warmed my stomach, and my heart, on many a wet walk or chilly cycle ride, often bolstered by a scone or a buttered bannock – soup is still taken seriously in Scotland, where you rarely find a cafe that doesn’t offer at least one example. The lentil variety is an old favourite that, you complicate “at your peril”, as Tom Morton explains in Shetland: Cooking on the Edge of the World (the book he wrote with his son James. as well as the island where I enjoyed an excellent bowl last autumn).. “Keep it simple.” But what’s the best way to do so?

The lentils

Lentils, and pulses in general, have been eaten in the UK for centuries, but were often dismissed as animal feed, fit only for the poor. Nevertheless, the poor, or at least the thrifty, did them justice. In that spirit, though I try recipes that specify red lentils, as well as a few that mention the green or brown variety, and some calling for just “lentils”, I’d advise you to use what you have to hand. Correspondents inform me that the red variety are more common in traditional Scottish cookery, and they do indeed break down more obligingly to thicken the broth, but, arguably, the brown sort have a deeper, more interesting flavour. Morton is clear, however: “Whatever meat or stock base you use, the key is red lentils, not soaked, but washed. For Shetland soup purposes, they should be cooked until they’ve almost dissolved.”

The vegetables

Everyone uses onions as a base, and Lindsey Bareham adds garlic and leeks as well, which, while they certainly won’t spoil the soup, do give it more of a continental character in the case of the garlic, and a slightly slimy element in the case of the leek. If you want to use a leek, I’d suggest adding it slightly later in the process, so it cooks through but doesn’t break down completely.

Potatoes feature in Bareham’s A Celebration of Soup, Katie Stewart’s Cookbook and Catherine Brown’s Classic Scots Cookery. Morton argues against their presence, however, and I tend to agree with him; the lentils are starchy enough on their own, though if you do want to bulk out the soup, I’d advise cutting the spuds into cubes, rather than Brown’s thin slices, which prove quite unwieldy to eat with a soup spoon.

Where Morton and I differ, though, is on the matter of neeps, or swede as I’d call them down in London. He won’t hear of them in this context, but I love their bittersweet flavour in both Brown’s and the Scottish Women’s Rural Institute’s (SWRI’s) recipes, and think it pairs nicely with the sweetness of the more popular carrots, too. I’m not a big fan of Bareham and Elisabeth Ayrton’s celery, preferring to stick with sweeter, starchier root vegetables, but, as with many such old recipes that were designed with thrift in mind, I’d encourage you to make use of what you have at home. This dish is a very good opportunity to see off whatever veg is languishing in the bottom of the fridge.

The stock

Stewart uses chicken stock, but everyone else calls for either ham stock, or a ham bone and water, making this the ideal final resting place for a Christmas ham bone that you might have taking up space in the freezer, or a canny way to stretch an already good-value ham hock even further. One joint can give you bountiful meat and stock for less than the price of a little packet of shredded ham hock, especially if you have a pressure cooker or similar. I quite like a smoky edge with the lentils, but, whether you go for smoked or unsmoked, cook it submerged in water until tender, then use the stock in the recipe below.

Ham stock isn’t easy to buy, but if you don’t want to faff around with a whole hock, many grocers and butchers should be willing to sell, or even give, you ham bones. Alternatively, nod to the idea by starting the soup off with fatty bacon, as Ayrton suggests in her book The Cookery of England, and use chicken stock instead. (If you eat chicken but not pork, you might like to add an extra spoonful of poultry or beef fat to the pan when frying the vegetables.)

I don’t find any recipes for making this soup with water, but it would no doubt often have been in lean times. The plant-based, however, would be better off with a good vegetable stock, plus a generous glug of oil for added richness.

Aromatics and flavourings

Our old friend bay leaf puts in an appearance in most recipes, but otherwise the aromatics tend to be quite restrained, with Brown and Ayrton adding parsley, and Brown thyme and celery or leek leaves, too. Bareham adds cloves, and Ayrton and the SWRI mace – in fact, the rural women are the most daring of the lot, because they finish their soup with curry powder. I like the peppery sweetness of mace (nutmeg would make a fine substitute), but, equally, you may well be content with bay and a few turns of the pepper mill.

Brown’s recipe has an intriguing sweet-and-sour flavour from the tomato puree, lemon juice and treacle she includes along with a dash of red wine, while Bareham also calls for lemon juice, albeit with white wine in her case, while Ayrton stirs in a little sugar. Though I’d prefer to use vegetables as sweeteners, a hint of acidity isn’t unwelcome at the end, especially if you’re serving this in spring, rather than the depths of winter.

Thickeners

Ayrton makes her white lentil soup with milk and finishes it off with double cream, so it’s extremely rich – nutty and delicious, too, but better served in small portions than steaming vats. Both she and the SWRI make use of flour (“lentil, rice or ordinary”, as the rural women put it), but I’m more taken with Bareham’s idea of pureeing a little of the soup, then stirring it back in to thicken the broth. If you value smoothness, you could put it all in a blender or even, in obedience to the SWRI recipe, pass it through a hair sieve, if you can find one, but I like the chunks of vegetable in Brown and Bareham’s versions, so I’m not going to bother.

To finish

Sippets of bread (as croutons were once called), chopped parsley and even olive oil are all suggested in the recipes I try, but you can’t beat a bannock.

Perfect lentil soup

Prep 15 min
Cook 1 hr
Serves 4

2 tbsp oil, or dripping
2 litres ham stock, or 1 ham bone or 150g chopped streaky bacon and 2 litres chicken stock (or water)
2 onions, peeled and finely chopped
2 large carrots, trimmed and cut into small dice
½ medium neep/swede, peeled and cut into small dice
250g lentils (I like red), washed
½ tsp ground mace
Salt and black pepper
1 bay leaf

Put the oil in a large saucepan on a medium heat, then fry the bacon, if using, until it browns lightly and the fat begins to render.

Add the onions, carrots and neep, and fry, stirring regularly, until the onion is golden and the other vegetables are starting to soften.

Stir in the lentils until they’re well coated in fat, then add the mace, a pinch of salt, a good grind of pepper and the bay leaf.

Now add the ham stock, or the ham bone and two litres of chicken stock or water, depending on what you’re using.

Bring to a simmer, then turn down the heat, partially cover the pan and leave to cook for about 45 minutes, until the vegetables are soft and the lentils have mostly broken down.

Remove and discard the bay leaf and ham bone, if necessary. Scoop out about a third of the soup, whizz it to a puree, then stir back into the pot. Adjust the seasoning to taste, and enjoy.

• Lentil soup: which is your favourite variety from around the world, and how is it served? Or are you of the Tudor opinion that lentils are best left to horses?