3 tbsp. butter
1 small onion, chopped
1 lb. assorted mushrooms, chopped
2 sprigs (leaves) fresh thyme or probably about ½ tsp dried
2 cloves garlic, minced
1/4 cup dry sherry
3 cups chicken broth
1 cup beef broth
1/2 cup half and half or heavy cream
salt and pepper to taste
Melt butter in stockpot or dutch oven. Add onions and cook until tender over medium-low heat, about 5 minutes. Add mushrooms, thyme, and garlic. Continue cooking over medium-low until mushrooms brown (do not add salt) and most of the moisture they've released has evaporated, about 15-20 minutes.
Add sherry. Switch heat to medium-high and cook until sherry is reduced by at least half, about 3 minutes.
Add broths. Simmer for about 20-30 minutes. Season to taste with salt and pepper.
Add half and half or cream and heat through over medium-low, about 5 minutes.
If you like a chunky soup, serve as is. If you like it smooth, puree with an immersion blender or food processor. If you are like me and like something in between, put a couple ladlefuls of the soup into a processor and pulse process. Re-add back to the soup and let it thicken slightly.