Fill your kettle and boil it. Peel and finely chop the onions. Trim the roots and the top 3cm off the leek. Slice a cross in the top of the leek, then open it out and rinse out any grit. Finely slice it.

Warm a large pan or casserole dish over a medium-low heat for 2 mins. Add 2 tbsp oil, the chopped veg and a pinch of salt and pepper. Cook for 10 mins, stirring occasionally, till the veg have started to soften. If they start to catch and burn, lower the heat and add a splash of water.

While the veg fry, peel and finely chop the carrots and parsnips. Peel and crush the garlic. Add the veg and garlic to the pan. Give everything a good stir, then cook for another 10 mins. Stir every so often, till the veg are soft. Fill and boil the kettle.

Meanwhile, halve and peel the swede. Chop it into chunks around 2cm across. Drain the butter beans and give them a rinse. When the veg are soft, add the swede and butter beans to the pan. Tip in the pearl barley. Crumble in the stock cube. Add the bouquet garni (if you have any heatproof string, tie the herbs together to make it easier to fish them out at the end).

Pour in 1 ltr boiling water from the kettle. Cover, bring to the boil, then turn the heat down. Simmer the stew for 30 mins till the veg and pearly barley are tender.

Roughly chop the parsley leaves. Lift the bouquet garni from the pan. Halve the lemon and squeeze in a little juice. Taste and add more lemon juice or a pinch more salt or pepper if you think it needs it. Ladle into warm bowls, and serve garnished with the parsley leaves.