Reduced-fat sour cream and low-fat milk make this soup creamy without all the fat. The pudgy brown mushrooms called cremini are generally firmer and richer-tasting than common white mushrooms.
Heat oil in a Dutch oven or soup pot over low heat. Add onion and cook, stirring until soft and translucent, 5 to 7 minutes. Add thyme and cook for 1 minute more. Stir in mushrooms, cover pot and steam until the mushrooms exude their moisture, about 5 minutes.
Sprinkle flour over the mushrooms. Increase heat to medium and cook, stirring, for 3 to 4 minutes. Gradually whisk in broth, scraping up any flour that clings to the pan. Simmer, stirring occasionally, until thickened and smooth, 5 to 7 minutes.
Combine sour cream and milk; whisk into the mushrooms. Season with salt and pepper. Gently heat until the soup is hot but not boiling. Just before serving, stir in lemon juice and sherry (if using).
Homemade Chicken Broth
1/2 starch, 1 vegetable, 1 1/2 fat
Quick and easy for a cold wintry night! I also added some diced potatoes and chopped spinach, but I bet it would be delish without it too! The thyme is a nice touch.