• 2 tablespoons cultured butter, divided
• 1 medium onion or 1 large leek (white and pale green parts), diced
• 1 pound mushrooms, sliced
• 2 teaspoons high-quality Hungarian paprika
• 2 tablespoons fresh dill, chopped, divided
• 1 teaspoon lemon juice
• 1 tablespoon flour
• 1⁄2 cup chicken or vegetable stock
• 1⁄2 cup whole milk
• Sea salt and freshly ground pepper, to taste
• 1⁄4 cup chilled sour cream (the thicker and tangier, the better)
1. In a deep, heavy-bottom saucepan set over medium heat, melt 1 tablespoon butter. Sauté onion or leek until they begin to soften, about 5 minutes. Add mushrooms, paprika and 1 tablespoon dill, and sauté 10 minutes more. Stir in lemon juice.
2. To make a roux that will thicken the soup, in a separate sauté pan set over medium-high heat, melt remaining tablespoon butter. Sprinkle flour over butter, and whisk continuously. Cook 5 to 10 minutes, or until roux goes from light blond to medium tan and becomes quite fragrant.
3. Whisk stock into roux until no lumps remain. Whisk roux mixture and milk into mushroom mixture. Heat to a low simmer. Season with salt and pepper. Reduce heat to low, and whisk in sour cream to warm it—do not boil. Serve hot, garnished with remaining dill. Serves 2.