Step 1

Place 3/4 cup sour cream in a small bowl. Juice 1/2 medium lemon (about 1 tablespoon) into the bowl of sour cream. Let sit on the counter until room temperature.

Step 2

Prepare the following, adding each to the same large bowl as it is completed: Dice 2 medium yellow onions (about 2 cups). Thinly slice 1 pound white button or cremini mushrooms, halving first if the mushrooms are larger than 1 1/2-inches in diameter.

Step 3

Prepare the following, adding each to the same small bowl as it is completed: Mince 4 garlic cloves. Finely chop 1/2 medium bunch fresh dill until you have 2 tablespoons (reserve a few dill fronds first for garnish if desired). Pick the leaves from 1/2 medium bunch fresh thyme and finely chop until you have 2 teaspoons. Add 2 teaspoons Hungarian sweet or hot paprika.

Step 4

Melt 4 tablespoons unsalted butter in a Dutch oven over medium heat. Add the onions, mushrooms, and 1 teaspoon kosher salt. Cook until the onions are translucent and the mushrooms are soft and have released most of their liquid, 12 to 14 minutes.

Step 5

Add the herb mixture, stir to combine, and cook until fragrant, about 1 minutes. Add 1/2 cup white wine and scrape up any browned bits from the bottom of the pot with a wooden spoon. Cook until the wine is mostly evaporated, 1 to 2 minutes.

Step 6

Add 3 cups low-sodium chicken or vegetable broth and 2 tablespoons Worcestershire sauce and stir to combine. Transfer about 1/4 cup of the liquid in the pot into the sour cream mixture and whisk to combine and set aside.

Step 7

Bring the soup to a simmer. Meanwhile, measure out 1 cup whole milk in a liquid measuring cup, add 2 tablespoons all-purpose flour, and whisk until smooth.

Step 8

Whisk the milk mixture into the soup and cook until the soup thickens enough to coat the back of a spoon, about 10 minutes. Remove the pot from the heat. Add the sour cream mixture and whisk to combine. Garnish with fresh dill fronds and a dollop of sour cream.