Amish Sauerkraut Soup

1 lb smoked sausage (kielbasa)
6 tbsp onion, chopped
1/4 cup flour
1/2 tsp thyme
1/2 tsp black pepper
3 cup milk
1 cup half-and-half
8 oz sauerkraut, with juice
1 1/2 tbsp lemon juice (optional)
2 tbsp fresh parsley, chopped

Chop the sausage coarsely by hand or in a food processor (leave the casing on). Transfer the sausage and onion to a deep pan, and saute over medium heat until the sausage is lightly browned, about 8 minutes. On a small plate combine the flour, thyme, and pepper. Add to the sausage and brown all together until the mixture bubbles up, about 5 minutes. Add the milk and the half-and-half all at once, and cook stirring until the mixture again bubbles up, about 5 minutes. Add the sauerkraut and it juice and bring to a boil; the mixture will continue to thicken. Taste for tartness, and lemon juice if desired. Add the parsley and serve at once.