Leeks, Cannellini Beans and Chard

Sometimes, the simplest-sounding things can surprise with new flavours and combinations.  This idea, from Riverford's first veggie book, sounded a bit ordinary, but I thought I'd use it to accompany a roasted leg of lamb.  It was delicious!  By all means, soak and cook your own beans, but I find that good-quality tinned ones are just as good - I use the brilliant Italian brand, Cirio, who steam their beans in the tin.  As a consequence, there is barely any liquid in the tin, so no wastage and a much better texture and taste.  It consists of a large, thinly-sliced leek and onion, sweated slowly in a knob of butter and dash of olive oil until soft and velvety.  Don't let it brown.  About 5 minutes before completely done, add a chopped clove of garlic and a teaspoon each of chopped fresh rosemary and thyme.  Add a tin of beans, drained and rinsed, and a handful of chopped chard or spinach leaves.  Add about 120ml of water or veggie stock, season, cover and simmer for a further 5 minutes until all is tender and amalgamated.  Really nice, and would make good soup with extra broth added.  As it was, it accompanied roast lamb and gravy perfectly, along with wedges of roasted Gem Squash.