Here's a simple, earthy, comforting soup for fall. If you don't have roasted garlic on hand (and don't have time to roast it before making the soup) just mince and saute several cloves along with the shallot and mushrooms.
1 large shallot or small onion, finely chopped
1/4 lb shiitake mushrooms, stemmed and finely chopped
2 1/2 lbs potatoes, cubed (no need to peel)
1 bay leaf
Chicken stock and/or water
1 head roasted garlic, cloves peeled
Salt and pepper to taste
Heat a little olive oil in a large pot. Add the shallot or onion and the shiitake mushrooms and saute for 3-4 minutes. Add the potatoes, bay leaf, and enough stock and/or water to cover. Bring to a boil, then reduce heat and simmer until the potatoes are tender, about 15-20 minutes.
When the potatoes are nice and tender, remove the bay leaf and add the roasted garlic. Puree the soup using an immersion blender (or do it in batches in a regular blender or food processor, then return to the pot). Add salt and pepper to taste.
Serve hot, topped with a small drizzle of olive oil if desired.