Autumn in the Balkans smells of roasted peppers and of jars lining up on balconies. Putting up preserves for winter is almost a ritual here, and yet in many kitchens the tomato sauce for pasta comes from a shop, in a jar with a label full of words that are hard to pronounce. There's no secret ingredient that sets them apart. Homemade sauce just needs time: 45 to 60 minutes on a low heat and zero rushing.

When you make the sauce yourself, you decide what goes into it. Shop-bought versions often contain additives and preservatives. At home, sugar is just a pinch to tame the acidity - or none at all - and salt and oil go in to taste. The sauce works for vegans, vegetarians, people with coeliac disease and lactose intolerance, and for children too, and it goes with pasta, rice, stews, roast meat and vegetables.

The tomato decides

Ripe, good-quality tomatoes make the biggest difference. Fresh ones need longer cooking because they hold more water. Peeled tinned tomatoes are practical all year round, and chopped tinned tomatoes are the quickest, but check the label for added sugar or thickeners. Chef Martín Berasategui has one more trick: once the vegetables have been sautéed, add a splash of white wine, let it evaporate, and only then add the tomatoes.

You'll need: 6 vine tomatoes, 2 cloves of garlic, 1 spring onion, 2 carrots, 1 leek, a pinch of salt, a pinch of sugar, extra virgin olive oil.

Method: Finely chop the garlic and spring onion, and the leek the same way. Dice the carrots, and cut the washed tomatoes into pieces, removing the stalks. Heat olive oil in a pan, sauté the garlic, then add the onion, followed by the leek, carrots and tomatoes. Salt as soon as the tomatoes go in. Let everything fry for a few minutes, cover and simmer on a low to medium heat for 45 to 60 minutes. The long cooking concentrates the flavours, evaporates the water and gives the sauce its proper thickness. At the end, uncover, blend and pass through a fine sieve for a smooth texture. Taste: if it's too sharp, a pinch of sugar sorts it out.

That's it. No magic, just the patience you won't find on any label. One big pot today means several evenings of pasta without a shop-bought jar. Will this sauce end up on the shelf next to the ajvar too?