1

Put the potatoes in a large pan of cold water and bring to the boil. Cook for 10-15 minutes, until soft. Drain and set aside to cool slightly, then mash.

2

Meanwhile, put the milk in a large shallow pan and bring to a simmer. Submerge the haddock in the milk and cover with a lid. Poach for 5-6 minutes, then remove from the heat. Once the fish is cool enough to handle, remove from the milk and flake, discarding the skin and the poaching liquid.

3

Add the fish, gherkins and thyme to the potato. Season and stir well to combine. Shape the mixture into four large fishcakes and chill for 15 minutes to firm up.

4

Preheat the oven to 200°C, fan 180°C, gas mark 6. Put the flour, egg and breadcrumbs in three separate shallow bowls. Dip each fishcake into the flour, then the egg, and finally the breadcrumbs.

5

Heat the oil in a large frying pan. Cook the fishcakes for 2 minutes on each side until golden, then transfer to a baking sheet and cook in the oven for 15 minutes.

6

Meanwhile, make the sauce by putting the watercress, crème fraîche and lemon juice in a food processor and blitzing until smooth. Season to taste.

7

Arrange the tomatoes and salad on plates, top with a fishcake and serve drizzled with the sauce.