Lentil Soup with Sausage

12 ounces brown lentils, washed
4 ouncs bacon, chopped
1 onion, thinly sliced
4 sticks celery, sliced
2 carrots, peeled, thinly sliced
3 tablespoons butter or margarine
3 to 4 bratwurst, cut into 1-inch pieces
1 tablespoon flour
2 tablespoons wine vinegar
Salt and pepper
1 cup water or stock

Soak lentils in a large bowl or stockpot with enough water to cover for 3 to 4 hours.

Drain and place in a large stockpot. Add bacon, onion, celery, carrots and 3 1/2 cups water. Bring to boil; cover and simmer for 45 minutes.

When lentils are almost cooked, melt butter in a frying pan and fry bratwurst until brown. Remove and set aside. Stir flour into butter in the pan and gradually whisk in additional water or stock. Bring to boil, stirring continuously. Add vinegar and seasonings and allow to boil for about 1 minute.

Stir the mixture into the soup, blending thoroughly. Bring back to boil and then allow the soup to simmer, uncovered, for a further 40 to 50 minutes, or until the lentils are completely tender. Add bratwurst and heat through.