Niçoise tuna with tender boiled eggs

Prepare the dressing by whisking together all the ingredients and seasoning generously with salt and pepper. Set aside.

Place the potatoes in a medium pot and fill it with cold water. Add one to two tablespoons of salt, cover with a lid and place over a high heat until the water boils. Lower the heat to a steady simmer and cook for 12-13 minutes, or until the potatoes are tender when pierced with a fork. Using a slotted spoon, drain the potatoes from the water and place on a plate to cool completely.

While the potatoes are cooking, lower the eggs into the water and cook for six minutes. Remove the eggs with a slotted spoon and plunge them in a bowl of ice water. Once they have cooled completely, carefully peel the eggs and slice in half.

Bring the pot of water back to the boil and add the green beans. Cook for three minutes before refreshing in a bowl of ice water and, once cooled, draining completely.

Arrange the baby gem and watercress leaves across a large serving platter, and top with the green beans, olives, tomatoes, eggs, radishes and potatoes. Break the tuna into large pieces and arrange in the centre of the platter. Scatter the capers over the top and drizzle generously with the prepared dressing.