Yesterday would have been a successful No Food Shopping Day if I hadn't had a Baldrick moment and succumbed to a few turnips to go with the leftover lamb. They weren't cheap either - £1.34 for three. I remember turnips going for pence. But they were good.
I cut them into large cubes, melted a bit of butter and oil in a pan, added a pinch of one of my regular standbys, Marigold organic vegetable bouillon powder (powdered stock) and a couple of tablespoons of water, put a lid on the pan and virtually steamed them for about 12 minutes. Much better than boiling them. (Carrots are good done the same way)
I cut up the leftover lamb, removing the excess fat and fried it in a very little oil until it was just beginning to crisp up, adding a pinch of the herb mixture I'd used when I roasted it the day before. Then I tipped in the leftover red wine sauce which had gratifyingly jellied. Instant stew.
Incidentally, this works much better than the old method of heating the meat and the leftover gravy up together IMO. Cooked meat tends to absorb any liquid it comes into contact with leaving you with an unattractive spongey, squelchy texture - which is why I don't like the old fashioned method of making shepherd pie with cooked lamb.
The 'fry first' method above works if you're making a curry from leftover meat too.