Place the lentils and bay leaf in a large saucepan and cover the lentils with water by about an inch and a half.
Cover and bring to a boil.
Turn down to medium heat.
Cook about 15 minutes or until the liquid is absorbed and lentils are tender.
Taste to see if the texture is done but not mushy.
Take out the bay leaf when done and discard. Set lentils aside.
While the lentils are cooking take the covering off of the sausage. Be careful when handling as you want to links to stay together.
Slice the sausage in 1/2" thick slices. Set aside.
Heat about a tablespoon of water in a large skillet.
Add the onion to the skillet and saute for about 10 minutes.
Preheat the oven to 350°.
Add the sausage and of the rest of the ingredients, including the cooked lentils to the skillet and mix gently but well.
Pour into a large casserole dish or two smaller ones so that you can freeze one.
Cover the casserole with a lid.
Bake at 350° for 20 minutes.