Start by melting butter (or heating olive oil) in a large soup pot over medium heat. Add the finely chopped onion and minced garlic. Sauté them for about 3–4 minutes, or until they’re soft and fragrant. This provides a flavorful base for your soup.

Sprinkle the flour over the sautéed onions and garlic. Stir everything together until the flour is fully absorbed, creating a thick paste. Cook for another minute to remove the raw flour taste.

Slowly pour in the chicken or beef broth while stirring to prevent lumps. Continue stirring and bring the mixture to a gentle simmer. Watch as the soup base begins to thicken.

Reduce the heat to low and stir in the heavy cream. The soup will take on a silky, luxurious texture at this point.

Now it’s time for the stars of the show. Add the diced corned beef and drained sauerkraut. Stir them in and allow the flavors to meld together. Simmer for 10 minutes.

Slowly stir in the shredded Swiss cheese, a little at a time, until it melts into the soup. Add Dijon mustard, caraway seeds (if using), and season with salt and black pepper. Simmer for another 5 minutes so all the flavors marry beautifully.

Remove the pot from heat and ladle your creamy Reuben soup into bowls. Garnish with a sprinkle of chopped fresh parsley for a pop of color and freshness. Serve immediately and enjoy!