Step 1

Heat 1 tbsp olive oil in a medium frying pan over a low-medium heat. Add the leeks and cook, stirring, for 10-12 minutes until soft. Add the sugar and vinegar and cook for 5 minutes or until sweet and sticky. Set aside.

Step 2

Wipe the frying pan with kitchen paper, then add another 1 tbsp oil and heat until almost smoking hot. Add the salmon fillets and cook for 4 minutes, skin-side down. Turn and cook for 4 minutes more until golden and just cooked through. Boil a kettleful of water. Put the kale in a colander, then pour over the boiling water.

Step 3

Put the salmon on a plate and cover with foil to keep warm. Add another 1 tbsp oil to the frying pan and, over a medium-high heat, stir-fry the wilted kale for 2 minutes. Add a good squeeze of lemon juice, then season with salt and pepper. Mix in the leeks and taste – it may need a little more vinegar. Divide the leeks and kale among plates and top with the fish. Serve with steamed potatoes if you like.