- 500g small, evenly sized waxy potatoes, such as Charlotte, peeled
- 4 x 200g tuna steaks, cut 3cm thick olive oil, for brushing
For the salsa verde
- 10g each of flat-leaf parsley leaves, mint leaves and basil leaves
- 1 garlic clove, thinly sliced
- 2tbsp salted capers, rinsed well, drained and dried
- 50g good quality pitted green olives
- 4 anchovy fillets in oil
- finely grated zest of ¼ lemon
- 1½tbsp lemon juice
- 1tsp Dijon mustard
- 8tbsp extra virgin olive oil
Cut the potatoes into 7-8mm thick slices. Put them into a pan of cold, well-salted water, bring to the boil and simmer for 5 minutes, or until they are only just tender when pierced with the tip of a knife. Drain well, leave the steam to die down, then toss them with 1tbsp olive oil and some sea salt and freshly ground black pepper.
For the salsa verde, drop the herbs into boiling water, leave for 5 seconds, then drain and refresh under cold water. Squeeze out the excess, then place on a board with the garlic, capers, olives and anchovies and finely chop everything together. Scoop the mixture into a bowl and stir in the lemon zest and juice, mustard, olive oil and some freshly ground black pepper.
Heat a cast-iron griddle over a high heat, then lower to medium. Add half the sliced potatoes in one layer and griddle for about 3 minutes on each side until golden. Transfer to a baking sheet, sprinkle with a little more sea salt and keep hot in the oven while you cook the remainder.
Brush the tuna steaks with oil and season. Return the griddle to a high heat and, when smoking hot, reduce to medium-high. Place them side by side on the griddle, reduce the heat to mediumhigh and cook for 1-1½ minutes on each side until striped on the outside but still rare in the centre. As you turn the tuna steaks over to cook the other side, divide the potatoes between 4 warmed plates. Place the fish on top, spoon over some of the salsa verde and serve.