Author Very slightly adapted from The Grape by Lisa Fain
Ingredients
8tablespoons(1 stick) unsalted butter
1/2mediumyellow onion, diced
2clovesgarlic, minced
1 1/2poundsbutton mushrooms, thinly sliced
1/4cupall-purpose flour
1 1/2quartsbeef or chicken broth
2tablespoonssherry (optional)
1tablespoonfresh thyme (leaves from 4 sprigs)
1bay leaf
1/2teaspoonkosher salt
1/2teaspoonblack pepper
1cupheavy cream
1/4teaspoonground nutmeg
Instructions
In a large pot, melt the butter on medium-low heat. Add the onions and while occasionally stirring, cook until just beginning to brown. Stir in the garlic and cook for 30 more seconds.
Add the mushrooms to the pot, and while occasionally stirring, cook until reduced and tender, about 5-7 minutes.
Stir in the flour until well combined with the vegetables, then cook for about 30 seconds or until fragrant and beginning to brown. Add to the pot the broth, sherry, thyme, bay leaf, salt, and pepper. Turn the heat to high, bring to a boil, then turn the heat down to low and simmer for 20 minutes.
Taste the soup and add more salt and pepper if needed. Add the heavy cream and nutmeg, then turn off the heat. Remove 1/4 cup of the sliced mushrooms for garnishing, then when the soup is no longer steaming (about 10 minutes), puree in batches in a blender. (Alternatively, you can puree in the pot with a stick blender.)
Serve warm garnished with sliced mushrooms.
Notes
A few changes I've made from The Grape's version: I cut the recipe in half, and I added more thyme and garlic. I also reduced the amount of flour, and while I haven't made it without, I think it would still be fine if you care not to include flour. The original recipe also didn't call for a sliced-mushroom garnish, though I think it's prettier that way.