1.5 kg (3 lb) thick piece of salmon, cut into 2 fillets
1 lemon, sliced
handful of mixed herbs, finely chopped
6 tablespoons mayonnaise
2 teaspoons drained capers, roughly chopped
1 spring onion, chopped
1 teaspoon caster sugar
1 teaspoon wholegrain mustard
lemon juice, to taste
handful of dill, chopped
Brush a large baking tray with a little of the oil. Place 1 salmon fillet, skin-side down, on the prepared sheet and season with a little salt. Top with the lemon slices and herbs. Season the other fillet and place on top, skin-side up.
Tie pieces of kitchen string around the salmon to secure. Drizzle over the remaining oil. Place in a preheated oven, 220°C (425°F), Gas Mark 7, for 25 minutes, or until just cooked through.
Meanwhile, mix together the sauce ingredients and place in a serving bowl. Serve alongside the fish with some buttered new potatoes and asparagus.