Method

• 1.
  Place the potato in a saucepan of cold, salted water. Bring to the boil, then reduce heat to medium and simmer for 15-20 minutes until tender. Drain.
• 2.
  Meanwhile, heat 1 tablespoon oil and half the butter in a non-stick frypan over medium-low heat. Cook the fennel, stirring, for 10-12 minutes until soft. Season, then mash with the potato, warm cream and remaining 15g butter until smooth. Chop most of the fennel fronds, then beat into the mash with a wooden spoon. Season and keep warm.

• 3.
  Combine the cornflour with 1 tablespoon freshly ground black pepper and 1 teaspoon salt flakes. Dust the fish fillets with seasoned cornflour. Heat remaining 1 tablespoon oil in a pan over medium-high heat. Cook fish, skin-side down, for 3-4 minutes until skin is crispy. Turn and cook for a further 1-2 minutes until almost cooked through but still a little rare in the centre.
• 4.
  Divide the fennel and potato mash among 4 serving plates, top with fish and sprinkle with remaining fennel fronds. Serve with rocket leaves and lemon.