Serves 6

200g/7oz dried borlotti beans, soaked in water for 12 hours
1 bunch of sage
1 head of garlic, sliced in half horizontally
20 little tomatoes, pierced with a small knife so they ooze juice into the cooking liquid
2 dried chillis, left whole
2 tbsp extra-virgin olive oil
1 tbsp red-wine vinegar
Enough water just to cover the beans

Drain the beans and place in a baking tray. Add the sage, garlic, tomatoes, chillis, oil and vinegar and cover with the water. Set your oven to 180C/350F/Gas4, cover the baking tray tightly with foil and place on the middle shelf. Cook for an hour, or until the beans are really tender. Remove from the oven and keep in a warm place.

For the butter

1 good-sized bunch of tarragon, leaves only
2 cloves of garlic, peeled and chopped finely
2 tsp Dijon mustard
3 good-quality anchovies
100g/31/2oz unsalted butter, softened
Freshly ground black pepper

Chop the tarragon finely and put in a bowl. Add the garlic and mustard. Chop the anchovies very finely and add. Cut the butter into cubes and add. Now beat together thoroughly to combine.

For the beef

200g/7oz fillet per person
A generous pinch of sea salt and plenty of freshly ground black pepper
1 tbsp olive oil

Place a large pan over a high flame. Season the meat very generously – it is important to use sea salt. Once the pan is hot, add the fillet and cook for five minutes on one side before turning and cooking for the same length of time on the underside. The fillet should have formed a delicious crust on the outside. Remove from the pan and wrap in foil. Set aside in a warm place for 20 minutes, then slice into eighth-of-an-inch pieces. Reheat the borlotti and spoon into bowls, lay the beef on top and spoon over the butter. Serve as soon as the butter has melted.

This dish is always very popular when I put it on at Petersham. It is warm and tender, with the spices given just a hint of sweetness by the prunes.