Nigel Slater makes bubble and squeak soup from Christmas leftovers on Nigel Slater’s New Year Suppers.

The ingredients are: a medium-sized onion, 2 tablespoons of dripping or butter, 750g leftover roasted or boiled potatoes and parsnips, 1 teaspoon chopped thyme leaves, 1.5 litres turkey, chicken or vegetable stock, salt and ground black pepper, 350g lightly cooked leftover greens (such as cabbage or Brussels sprouts), 150ml single cream and a fine grating of fresh nutmeg.