Artichoke gratin

I am all for frozen vegetables, especially when used for hearty, long-cooked dishes like this one. Here, in particular, you’ll save yourself tons of work if you can get a couple of bags of frozen artichoke hearts, without sacrificing much flavour. I get them where I do most of my grocery shopping, at the Lebanese mini-supermarket Green Valley, just off Edgware Road in west London. It’s an Aladdin’s cave full of Middle Eastern treasures. Try there or in other Middle Eastern grocers. Serve th