White bean and onion soup with fresh thyme

This deliciously light but flavourful and filling soup is the perfect January antidote to a overindulgent December. Serves 4

60g butter

1kg onions, sliced as thinly as you possibly can

1/2 tbsp yellow mustard seeds

1 tbsp chopped fresh thyme leaves

3 tablespoons cider vinegar

1.5 litres chicken stock

One tin of cannellini beans, drained

3tbsp single cream

one short baguette sliced very thinly

60g finely grated gruyere

chopped parsley to serve

salt and pepper

Melt the butter and cook the onions very s-l-o-w-l-y. It might take up to half an hour, but be patient.

Tip in the mustard seeds, cook for a few minutes, then add the thyme and vinegar. Turn up the heat while the vinegar is absorbed. Add the stock and bring to the boil, then reduce the heat and simmer gently for 30 minutes. Pour in the beans and heat through, then mash with a potato masher in the pan, not to a pulp, just until the colour starts to lighten and you have lots of nice crunchy lumps. Keep warm.

Lay thin slices of baguette on the grill, drizzle lightly with olive oil and slide under a hot grill until golden. Turn over and sprinkle with grated gruyere . Pop back under the grill until melted, then remove and keep warm. Take the soup off the heat and swirl through the cream. Season to taste and sail the cheese toasties on the top, scattered with parsley.