Heat a generous glug of extra virgin olive oil in a large pot on a medium heat. Peel and halve onion lengthwise then finely slice into half moons. Cook onion, covered stirring every now and then for about 8 minutes or until the onion is soft but not browned.

While the onion is cooking tear leaves from the stems of your greens into bite sized chunks (or thickly slice into ribbons). Keep stems separately and finely slice them.

When the onion is soft add anchovies (if using) and cook for another minute so they flavour the oil and start to melt into the sauce.

Add the sliced stems and cook, covered for 10 minutes or until starting to soften.

Pile torn / sliced leaves into the pot. Add stock or water and a pinch of salt. Cover with your lid and cook for another 10 minutes, stirring every now and then. When the leaves are tender, taste and season with extra salt if needed.