Halve one of your pears. Scoop out the seeds from one of the halves. Peel it and pop the pear half in a food processor or blender with 100ml water (see our tip if you don’t have one). Crush 4 cardamom pods and shake in the black seeds. Finely grate in the lemon zest and squeeze in the juice from one half. Season and blitz to a purée.
Lay the chicken breasts between 2 pieces of cling film and bash with a rolling pin a few times to flatten them. Prick them all over with a fork. Pop the chicken breasts in a dish and spoon over half the pear purée. Rub it into the chicken.
Warm a large frying pan over a high heat for 2 mins. Add 1 tbsp oil. Put the chicken breasts in the pan. Fry for 2-3 mins on each side till browned and cooked through – the juices should run clear when you pierce them with a skewer. Transfer the chicken to a board, loosely cover with foil and leave to rest while you make the rest of the salad.
Halve the fennel bulb and cut into 2 cm thick wedges. Peel and core the remaining 1½ pears. Slice them into similar sized wedges.
Put the frying pan back on the heat and add 1 tsp oil. Add the fennel and pear wedges. Fry for around 10 mins, turning a few times till nicely golden and a little charred around the edges. You may need to do this in 2 batches if your pan isn’t big enough.
Tip the charred veg into a large bowl. Add the watercress and the remaining pear purée. Toss together to mix.
Tip the walnuts into the frying pan. Toast for 2-3 mins till they’ve browned a little. Serve the chicken with the salad, scattered with the toasted walnuts.