4 sausages, cut into fork-sized discs (you can't do this neatly - no matter)
80g smoked pancetta, cubed
2tbsp olive oil
1 onion, chopped
2 cloves garlic, chopped
150g lentils, Puy or Puy-type, rinsed
250ml (or more) chicken stock (I used half a cube, and water)
1 bay leaf
1 dried chilli
A few splashes of Worcester sauce
In a heavy pan or casserole, fry the sausage chunks and pancetta in the oil, over a low to medium heat. Don't turn up the heat too high: the oil will burn, and bits of sausage will stick to the pan and burn too. Be patient until the meat starts to brown - about 10 to 15 minutes.
I don't think you need to remove the sausage from the pan now, as McEvedy advises. Throw in the onion and garlic, and keep everything moving until the onions have softened - five to 10 minutes.
Tip in the lentils with the stock, bay leaf, chilli, and sauce (optional). You want enough liquid just to keep the lentils submerged. Bring the contents of the pan to a simmer, cover it, and continue cooking on a very low heat. Check from time to time, because the lentils will absorb some of the liquid, which you may need to top up.
The trick is to maintain the liquid at a level that will cook the lentils but that will not leave you with a very sloppy stew. They may take 45 minutes to an hour to tenderise - about twice as long as normal. When they're soft enough, remove the pan lid to allow some liquid to evaporate.
Test the seasoning. You can add salt now: if you had done so earlier, it might have toughened the lentils. If you have parsley, chop it and stir it in.