Tip the pearl barley into a small pan and pour in 300ml boiling water. Add a pinch of salt and pop on a lid. Bring to the boil, then turn the heat down and simmer for 15-20 mins till the barley is tender but still with a little bite.
While the barley simmers, tear the soft kale leaves off their cores, then chop the kale leaves into bitesized pieces. Set aside.
Thickly slice the portobello mushrooms. Halve any large button mushrooms. Peel and finely slice the shallots.
Warm 2 tbsp olive oil in a large frying pan or wok, over a medium heat. Add the mushrooms with a pinch of salt and pepper. Gently cook, stirring often, for 10 mins till the mushrooms are browned all over and you’ve cooked off most of the mushrooms’ liquid.
Stir the shallots into the mushrooms and fry, stirring often, for 4 mins till the shallots have softened and browned.
Halve the lemon and squeeze the juice of 1 half into the mushrooms. Add 2 tbsp tamari and 1 tbsp sesame oil. Toss in the kale leaves. Cook, stirring, for 3-4 mins till the kale leaves have started to wilt.
If you haven’t already drained the barley by now, drain it and shake in the sieve or colander to shake off any excess water. Tip into the kale and mushrooms. Gently toss to mix, then spoon the salad onto warm plates and serve.