It is funny that such a cheffy term should describe such a simple trio. But mirepoix, the combination of celery, carrots and onions, provides a flavour-some base for soups and stews.

It’s also the base for this week’s recipe, and I’ve included mirepoix veg on the shopping list even though they were on it last week (see timesonline.co.uk/realfood for the ongoing list) because they are such important staples. I’ve often wondered who discovers combinations such as mirepoix or who first put mint sauce with lamb. Who found out that chestnuts and bacon was a match made in heaven?

The weather is foul so I’m yearning for root vegetables to give me the ammunition to fight the cold and natural sugars to give me a boost. Yesterday I couldn’t resist buying a head of celeriac. It is such a richly flavoured vegetable that its presence helps to make the winter food season as exhilarating as the spring one.

Celeriac is delicious in a creamy soup, great roasted with spuds, and comes into its own in a gratin. I know sausages and mash are naturals, but sausages with celeriac gratin are equally satisfying. In the main recipe, I’ve added it to flavour the mirepoix and add body to the greens.

My boyfriend Mark thought “greens” was a generic term for all vegetables. When I said it was also the name for a particular leafy vegetable that looks a bit like spinach, he was intrigued. I explained that greens are rich in antioxidants, grown here in Britain and full of flavour. What’s more, they are cheap.

Sweated in olive oil with bacon and chestnuts, greens make a delicious light supper. Mark polished off the lot, despite the fact that the recipe (right) should feed three or four. The sweetness of the chestnuts melds beautifully with the salty bacon and the whole recipe goes halfway to making a lovely emerald green soup later in the week.

Shopping list

1 small head celeriac
1 loaf of bread
700g greens (before cooking, wash, remove stalks and slice)
1 packet streaky bacon or pancetta
2 packets vacuum-packed chestnuts
700g spinach (before cooking, wash, remove stems, or buy 2 packets prepared spinach)
1 bunch of fresh thyme

And if you don’t have them already...

1 bunch carrots
1 bag of onions
1 head celery
1 head garlic
1 bag of potatoes
300ml double cream

Store cupboard buy

1 bottle of good quality sherry vinegar for salad dressings and seasoning dishes

Star buy

A wedge of parmigiano reggiano or the cheaper gran padano. Keep it in the fridge wrapped in greaseproof paper. A good deli will sell you a fat chunk, which should last you for weeks

Sautéed greens with chestnuts

Equipment needed

1 large heavy-bottomed pan, a chopping board, knife and a wooden spoon.

Preparation time: 20 minutes Cooking time: 15 minutes Serves 3-4

Peel three carrots, three onions and half a head (about 200g) of celeriac and cut them into small (1cm/½in) dice, together with three sticks of celery. Melt 2 tbsp of butter and 2 tbsp of olive oil in the heavy pan and add the vegetables. Throw in a few sprigs of fresh thyme, season with salt and pepper and cook over a medium heat for about five minutes. Remove half the vegetables, cool and store in the fridge for use in the spinach soup (right) later in the week.

Add 150g diced, streaky bacon or pancetta and 150g diced chestnuts to the remaining veg. Sautée for a further five minutes over a fairly high heat so that the bacon fat melts. Throw in the winter greens with about 100ml (3½fl oz) of water and a generous seasoning of salt and pepper and cook for another 5 to 10 minutes, until most of the water has evaporated and the greens still have some bite. Add a splash of sherry vinegar to sharpen the taste. Serve each helping with a slice of toast, rubbed with the cut side of a garlic clove and a good drizzle of extra-virgin olive oil.

Nutritionist’s verdict

Tuck in... for vitamins

This is packed with vitamins, minerals and fibre. It also has calcium, iron for energy, plus a good slug of zinc and selenium to boost immunity. But not all salads are low in calories: this contains 522 per portion (serving four).

Second helpings

1. Spinach soup Take the set-aside veg from the main recipe (left) and put in a large casserole. Heat and add 1 litre (1¾ pints) of water (or stock). Simmer for five minutes and add the spinach. Cook for three minutes before blending. Season to taste and serve with garlic croutons and parmesan or a swizzle of crème fraîche and a grating of nutmeg. Use any leftover soup mixed with crème fraîche as a sauce for fish.

2. Celeriac gratin Peel and slice the remaining half a head of celeriac with an equal quantity of peeled, sliced potatoes. Cover with salted water and simmer for 15 minutes. Drain and arrange in layers with a sliced onion in an ovenproof dish. Season well, pour over 150ml cream, scatter with breadcrumbs from your loaf, dot with butter and scatter with a grating of parmesan cheese. Bake in a hot oven (200C/390F) for 20 minutes until golden on top. Serve with sausages, roast chicken or eat on its own with a green salad.

Look up Thomasina's store cupboard essentials and recipes at timesonline.co.uk/realfood

Plus find the best ingredients in your area. For more tips on reducing food waste, go to lovefoodhatewaste.com

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