Parsnip and apple soup for the first cold week

When the evenings turn properly cold, I want soup that is a little sweet, a little peppery and thick enough to hold a spoon. Parsnip and apple is the one I make most in late autumn. Parsnips get sweeter once the weather is cold, a sharp apple keeps the soup from tasting heavy, and the whole pot costs very little.

For four bowls I use 600 g of parsnips, one large cooking apple or two sharp eating apples, one onion, a clove of garlic, a knob of butter or a spoonful of oil, a teaspoon of mild curry powder or ground cumin, and a litre of vegetable or chicken stock.

I peel the parsnips and cut them into chunks the same size, so they cook evenly. A big old parsnip often has a hard woody core down the middle. I cut it out, because it never softens and leaves stringy bits in the soup. I peel and core the apple and cut it into pieces too.

In a large pan I soften the chopped onion in the butter over a low heat for about eight minutes, until it is soft and sweet but not brown. Then the garlic and the spice go in for one minute, just until they smell warm. I add the parsnips and the apple and stir them round so they are coated, then pour in the hot stock.

The soup simmers with the lid half on for 20 to 25 minutes, until a parsnip chunk breaks easily against the side of the pan with a spoon. Then I take it off the heat and let it stand for a few minutes before blending.

Blending hot soup needs care. I never fill a jug blender more than half full with hot liquid, I hold the lid down with a folded tea towel, and I start on the lowest speed, because steam can push the lid off and spray boiling soup. A stick blender in the pan is easier and safer; I keep the blade under the surface.

When it is smooth, I taste it. It usually needs salt, a few grinds of black pepper, and sometimes a little more stock or water if it is too thick. A splash of cream or milk makes it softer; a squeeze of lemon makes it brighter.

On top I put a swirl of yoghurt, a few crispy fried sage leaves, or some toasted seeds. With a piece of good bread, it is a whole supper.

Soup is easy to make ahead, but cooling is where most mistakes happen. A large pot of hot soup cools very slowly. So I pour what we are not eating into shallow containers, let them cool, and put them in the fridge within two hours. In the fridge it keeps for up to two days. I reheat only the portion we are eating, in a pan, until it is steaming hot all the way through, and I do not reheat the same portion twice.

It also freezes very well, for up to three months. I leave a little space at the top of each container, because soup expands as it freezes, and I defrost it overnight in the fridge before reheating.

For anyone feeding a baby, I keep a portion back before adding salt, and use unsalted homemade stock or water, because babies should not have salty food or ordinary stock cubes.

Parsnip and apple soup. Serves 4. About 40 minutes. You need 600 g parsnips, 1 large cooking apple, 1 onion, 1 garlic clove, a knob of butter, 1 tsp mild curry powder or cumin and 1 litre stock. Soften the onion, add the garlic and spice, then the parsnips, apple and stock. Simmer for 20–25 minutes, blend carefully and season.

What soup do you make when the cold arrives?