Fill and boil your kettle. Tip the pearl barley into a small pan. Pour in 250ml boiling water and add a pinch of salt. Bring to the boil, cover with a lid then turn the heat down and simmer for 20-25 mins, till the barley is tender but still has a bit of chew to it. If the pan starts to dry out, add a splash more water – the barley will absorb some, but there should still be water left in the pan.

Meanwhile, peel and grate the garlic into a small bowl. Squeeze in the lemon juice and add 1 tsp Dijon mustard, 1 tbsp olive oil and a pinch of salt and pepper. Whisk with a fork to make a dressing.

Trim the ends off the celery sticks and thinly slice them. Peel and thinly slice the red onion. Quarter the apples, cut out the cores and slice the quarters into thin wedges. Cut the cheddar into small cubes. Add the celery, onion, apples and cheese to a large salad bowl.

When the pearl barley is cooked, drain it if necessary and allow to cool for 2-3 mins. Tip the barley into the salad bowl. Pour over the mustard dressing and add the watercress. Fold everything together and serve.