Mix the lemon zest and juice with the capers and 1 tbsp oil to make the dressing. Boil the leek and beans together with a little salt for 6-8 mins until tender. Lift them out with a slotted spoon, set aside, then add the spinach to the pan to wilt for 1-2 mins.

Meanwhile, heat 1 tsp oil in a non-stick pan over a medium heat and fry the salmon, skin-side down for 4 mins. Turn to cook the other side for 2-4 mins, or until just cooked through. Add a couple of spoonfuls of the broad beans to the dressing then, using a hand blender, small food processor or a fork, blitz the rest of the beans with the leek to a purée, adding a splash of cooking water if it’s too thick. Drain the spinach well and divide between plates, spoon on the purée, then top with salmon. Spoon over the dressing, scatter over the basil and serve with potatoes.