potato fennel soup with browned onions

1 tbsp butter or oil
4 cups thinly sliced onions
2 tsp salt
4 medium potatoes, sliced into thin pieces 1 to 2 inches long (don't bother peeling!)
1 cup freshly minced fennel bulb
1/2 tsp caraway seeds
4 cups water
white pepper to taste

optional toppings:
sour cream, fennel tips

melt butter (or heat oil) in large pot. Add onions and 1 tsp salt. Cook over medium heat, stirring occasionally, until onions are very very soft, and lightly browned (15 - 20 minutes).

add potatoes, another 1/2 tsp salt, minced fennel and caraway seeds. Sauté over medium heat for another 5 minutes, then add water. Partially cover, and simmer until potatoes are tender (10 - 15 minutes.)

taste for seasoning, and adjust if required. Garnish if you wish.