1 C. navy beans
1 small onion chopped
1 leek rinsed and chopped
2 T. vegetable oil
1 medium carrot diced
3 garlic cloves minced
1 t. salt or to taste
1/4 t. ground black pepper or to taste
1 1/2 t. sweet Hungarian paprika
3 T. unbleached white flour
1/4 C. sour cream
2 t. cider vinegar or 1-2 T. fresh lemon juice
2 T. chopped fresh parsley

Soak the navy beans in plenty of water overnight. Drain the beans and place in a 4 quart pot. Add water to an inch above the level of the beans. Bring them to a boil and then simmer, covered untill tender, about 1 1/2 hours. Add more water as needed to keep the beans covered with about an inch of water.
In a seperate saucepan saute the onion and leek in the oil untill the onion is translucent. Add the carrot and garlic and continue to saute for several minutes. Mix in the salt, pepper and paprika. Sprinkle the flour into the vegetables, stir well, and cook for a few minutes more.
Ladle out 2 cups of the hot bean water and slowly stir it into the vegetable mixture untill smooth and thickened.
Add the vegetables to the pot of cooked beans, stirring constantly.
Remove the soup from the heat and whisk in the sour cream and then the vinegar or lemon juice. Gently reheat the soup for about 10 minutes, stirring frequently. Just before serving add the parsley.
If the soup is too thick thin it by adding a little hot water or vegetable stock. If it is too thin thicken it by cooking a few minutes longer.