A delicious mushroom soup recipe from Merchant restaurant in Madison, Wisconsin.
6 tablespoons butter
1 cup onion, diced
2 teaspoons kosher salt
1 teaspoon freshly ground black pepper
½ cup all-purpose flour
1 tablespoon fresh thyme leaves removed from stems
1 large bay leaf
2 quarts vegetable broth (homemade or store bought)
2 pounds mushrooms coarsely chopped or sliced, see note below*
2 tablespoons black garlic sliced, see note below**
1 cup heavy cream
¼ cup loosely packed fresh basil
¼ cup loosely packed fresh flat-leaf parsley
In a large Dutch oven or heavy bottomed pot, melt butter over medium heat and add onions.
Sauté onions for a full ten minutes, stirring often. They will begin to brown.
Keep heat at medium and add salt, pepper, flour, thyme and bay leaf and stir to create a roux.
Cook the roux for four minutes, stirring often.
Add the vegetable broth one third at a time, whisking as you add.
Once the mixture is creamy and all of the roux mixed into the broth, add the mushrooms and garlic.
Bring to a slight boil, reduce to a medium simmer and cook for 15 minutes, stirring often so it does not stick to the bottom.
Remove and discard the bay leaf.
Add cream and heat just to get the soup back to temperature and then add the fresh basil and parsley.
Using an immersion blender or a regular blender, purée completely until creamy.
Adjust salt and pepper to taste as needed and serve.
*Note: Mushrooms should be half Cremini (baby Bella) and half other edible mushrooms. I used a combination of Oyster, King Oyster, Shiitake and Hen of the Woods. Each should be cleaned as appropriate. For Shiitake, remove and discard stems. If the Oyster and Hen of the Woods have dirty root ends, cut off and discard. Once cleaned, you should have two pounds total. If you only have the Cremini available, then use all Cremini. I would not recommend regular white button mushrooms as they do not have a strong enough flavor for this soup.
If you only have dried mushrooms available to you, reconstitute and drain out any water.
**Note: Black garlic can be found online, at Asian specialty markets (in prepackaged bags), and at some Trader Joe’s supermarkets. Black garlic is strong and concentrated and is actually just regular garlic that has been put through an fermentation process. If you cannot find black garlic, feel free to roast your own. Then just squeeze the cloves to extract the now-soft garlic.