Confit Tuna with Herb Potatoes and Shellfish Vinaigrette

Ingredients

For the confit tuna

• 200ml/7fl oz olive oil
• 2 x 200g/7oz tuna steaks
• 150g/5½oz cherry vine tomatoes, still on the vine
• 1 rosemary stick
• 2 garlic cloves, smashed
• 1 bay leaf
• 50g/1¾oz bottarga or mojama (air-dried tuna loin), grated, to garnish

For the shellfish dressing

• 3 tbsp olive oil
• 1 banana shallot, peeled and chopped
• 1 garlic clove, chopped
• few thyme sprigs
• 200g/7oz clams, scrubbed and debearded
• 200g/7oz mussels, scrubbed and debearded
• 200g/7oz cockles, cleaned thoroughly
• 150ml/5fl oz Amontillado sherry
• 1 tbsp red wine vinegar
• salt and freshly ground black pepper
• 1 tbsp roughly chopped fresh flat-leaf parsley
• 1 tbsp roughly chopped fresh tarragon

For the herb potatoes

• 6 waxy new potatoes, peeled
• 1 tbsp chopped fresh flat-leaf parsley
• 1 tsp chopped fresh tarragon
• 1 banana shallot, peeled and diced
• 3 tbsp olive oil
• 1 tbsp sherry vinegar

Method

1. Preheat the oven to 120°C (100°C fan)/Gas ½. This low temperature will gently confit the tuna, keeping it moist and tender while allowing the flavors of the oil, garlic and herbs to infuse.

2. In a shallow roasting tin, combine the olive oil, tuna steaks, cherry vine tomatoes, rosemary stick, smashed garlic and bay leaf. Press the ingredients down so the oil covers everything. Cover the tin tightly with foil and place it in the oven. Cook for about 2 hours, or until the tuna flakes easily and is very soft. Remove from the oven and leave the tuna and tomatoes in the oil to cool slightly; this preserves moisture and concentrates the flavors.

3. While the tuna is confiting, prepare the shellfish dressing. Heat 1 tablespoon of the olive oil in a large saucepan or casserole over medium heat. Add the chopped shallot, garlic and thyme and sweat for 2–3 minutes until softened but not browned. Check the shellfish and discard any with cracked shells or any that do not close when tapped.

   Add the cockles, clams and mussels to the pan, pour in the Amontillado sherry, cover with a lid and steam until the shells open. Remove from the heat and discard any shellfish that remain closed. Strain the contents through muslin or a fine sieve, reserving the cooking liquor in a bowl. Pick the shellfish meat from the shells and set aside. To make the dressing, whisk together the reserved cooking liquor, the picked shellfish meat, the remaining olive oil and the red wine vinegar. Season with salt and freshly ground black pepper, then fold in the chopped parsley and tarragon to finish the shellfish dressing.

4. Cook the herb potatoes by bringing a large pan of salted water to the boil. Add the peeled waxy new potatoes and simmer until tender when pierced with a fork. Drain well and return to the pan or a bowl; crush the potatoes lightly to break them up while keeping some texture. Mix in the chopped parsley, tarragon and diced shallot, then drizzle with the remaining olive oil and sherry vinegar. Taste and adjust seasoning.

   Gently fold the confit tomatoes and flaked tuna into the herb potatoes, taking care not to break the tuna into tiny pieces — you want delicate flakes. Dress the whole mixture with the warm shellfish dressing so the potatoes and fish soak up the aromatic liquor. Finish by grating the bottarga or mojama over the top for a salty, umami-rich garnish. Serve immediately while warm.

Recipe notes: This confit tuna with shellfish dressing and herb potatoes makes an elegant main course for two. Use the best-quality tuna and fresh shellfish you can find for maximum flavor. The dish benefits from resting a short time after assembly to allow the dressing to meld with the potatoes and fish. Leftovers can be refrigerated and enjoyed the next day, though the texture is best on the day of cooking.