1. Drain the white kidney beans and place in a large saucepan. Add a sprig of sage, peppercorns and the garlic clove. Cover generously with water.

2. Bring to the boil, reduce the heat and simmer for 1 hour until tender. Season with salt just before the end of the cooking period. Drain the white beans and discard the sage, peppercorns and garlic.

3. Pick the sage leaves off their stalks. Pour the vegetable oil into a small frying pan until it reaches 1 cm up the side of the pan.

4. Heat the oil and fry the leaves until crispy. Remove the leaves with a slotted spoon and drain on kitchen paper.

5. Mix together the remaining olive oil and the wine vinegar, making a vinaigrette. Season with salt and freshly ground pepper.

6. Toss together the white beans, tomatoes and onion. Toss with the vinaigrette. Garnish with the fried sage leaves and serve.