Seared tuna steaks and nicoise salad

Method

1. Bring a medium pan of water to the boil with a pinch of salt. Add the potatoes and cook for 10 minutes. Add the beans and cook for a further 3 minutes until tender. Drain and refresh under cold water, then drain well, pat dry and set aside.
2. Meanwhile, combine the onion slices, vinegar, sugar, salt and a pinch of pepper in a small bowl. Add 1 tbsp water and set aside for 15 minutes to quick-pickle. Drain well and put in the fridge.
3. Put the eggs in a saucepan of gently boiling water and simmer for 7 minutes. Drain and plunge into cold water. Peel and cut in half (or see Make Ahead).
4. Heat a griddle pan or heavy-based frying pan over a high heat. Rub the tuna with the olive oil and season. Add to the pan and cook for 1-2 minutes on each side, depending on the size of the steaks. (The tuna should be cooked on the outside but rare in the middle – similar to beef carpaccio.) Remove from the pan and rest for 5 minutes, then cut into thin slices, cover and chill until needed.
5. For the dressing, whisk all the ingredients together in a small bowl. In a separate bowl or container, combine the potatoes, beans, tomatoes, anchovies, caper, olives, herbs and rocket leaves. Add a couple of tablespoons of the dressing and stir well (see Make Ahead).
6. To assemble, transfer the salad to a big plate or platter and arrange the tuna slices on top. Drizzle over the remaining dressing just before serving.