1. Prepare the beef

Pat the beef dry and cut it into bite-sized pieces. Season with salt, black pepper, and paprika. For extra flavor, heat the olive oil in a skillet and brown the beef in batches for 2–3 minutes per side. Transfer to the slow cooker.

2. Add the vegetables

Add the chopped onion, minced garlic, sliced mushrooms, and diced carrots to the slow cooker. Stir in the Worcestershire sauce, Dijon mustard, thyme, and tomato paste if using.

3. Add the broth

Pour in the beef broth and stir gently to combine. Cover with the lid and cook on low for 6–8 hours or high for 3–4 hours, until the beef is fork-tender.

4. Thicken the soup

About 30 minutes before serving, whisk the flour with a little cold water to make a smooth slurry. Stir it into the soup. Alternatively, mix the flour with softened butter to make a paste before adding it. Cover and cook for another 20–30 minutes, stirring occasionally if convenient.

5. Cook the noodles

Add the egg noodles during the final 15–25 minutes of cooking, depending on the package instructions. Stir occasionally and check that the noodles are tender but not mushy.

Tip: For leftovers or a make-ahead meal, cook the noodles separately and add them to each bowl just before serving. This prevents them from soaking up too much broth.

6. Make it creamy

In a small bowl, stir a few spoonfuls of hot broth into the sour cream to temper it. Reduce the slow cooker to warm, then stir in the sour cream and heavy cream. Avoid boiling the soup after adding the dairy, as it may separate. Taste and adjust the salt and pepper.

7. Garnish and serve

Ladle the hot soup into bowls. Garnish with chopped fresh parsley and a little freshly cracked black pepper. Serve immediately with crusty bread or garlic toast.