Causa from A Passion for Potatoes by Paul Gayler

Ingredients

• 350 g (12 oz) new potatoes
• A good pinch of saffron strands
• 350 g (12 oz) truffle potatoes (black potatoes)
• 1 habanero chilli, deseeded and finely chopped
• 4 spring onions, finely chopped
• 2 anchovy fillets, finely chopped
• 2 plum tomatoes, cut into 5mm (¼ in) dice
• 1 tablespoon chopped coriander
• Juice and finely grated zest of 1 lime
• 1 teaspoon baby capers, rinsed and drained
• 1 tablespoon honey
• 6 tablespoons olive oil
• 75 g (3 oz) unsalted butter
• 4 tablespoons good-quality mayonnaise
• 175 g (6 oz) canned tuna in olive oil, drained
• Salt and freshly ground black pepper
• 1 garlic clove, crushed
• 2 tablespoons vegetable oil
• A pinch of ground cumin