Sounds tasty! I've made lentils with onion but haven't tried leeks.

You stirred the sausage into the lentils, or the lentils into the sausage? (I have a suspicion that you'd get some nice effect by doing the latter, letting the lentils soak up the pan drippings and get that saute "browning" effect a bit, though I also grant that tofurky doesn't produce the same kinds of drippings as meat.)