I craved lentils when pregnant too, I made vats full of this Nigel Slater recipe and just ate it four times a day. It is so delicious. I didn't even bother with the sausages most of the time either. I never added parsley or celery, but doubled the carrot and put loads and loads of black pepper in.
2 tbsp olive oil
120g streaky bacon, diced
1 onion
1 large carrot
a rib of celery
300g green lentils
1 litre chicken stock
2 bay leaves
8 plump pork sausages
chopped parsley
Warm the oil in a deep, heavy casserole. Put the bacon in and let it cook over a medium heat so it colours lightly. Meanwhile, peel the onion, chop it finely and add to the bacon. Cut the carrot and celery into rough dice, and stir them in, letting them soften a little. Don't let them colour. Tip in the lentils, pour in the chicken stock, then tuck in the bay leaves and sausages, cut into short lengths if you prefer, and bring to the boil. Turn down the heat so the liquid simmers gently, season, then leave it for 30 minutes, stirring from time to time. Check the seasoning (I like it peppery), and stir in a handful of chopped parsley.
Another good recipe is the puy lentil lasagne on the bbc website.