5-6 medium sized potatoes
half a bunch of green onions, sliced
1 (or more) shiitake or Chinese black mushroom (I also like to toss in a few dried porcini mushrooms)
1 chicken leg
1 cup milk
pepper
bay leaves
 

From Leona's Kitchen 

Soak the mushroom in hot water for 30-45 minutes.

Peel and slice the potatoes.  Saute the onions in a little bit of olive oil over medium heat. 
Add the potatoes and a quart of water. 
Put in the bay leaves and the chicken leg. 
Simmer for an hour.

Dice the mushroom and add the mushroom pieces and the soaking water to the soup.

When the potatoes are done, smash them with a fork or a potato masher and stir the soup well. 
Add the milk and season with salt and pepper.

Oh, before you smash the potatoes, take the chicken leg out and cut the chicken into little pieces and add it back in.

Note:
If you're watching your cholesterol, leave out the chicken and the milk.  The soup is still good without them.