Brown the Beef: Heat 1 tablespoon of olive oil in a large pot over high heat. Pat the beef dry with paper towels, season with salt and pepper, and sear in batches until well-browned on all sides. Remove and set aside.
1 tablespoon olive oil, 1 pound stewing beef, ½ teaspoon salt, ½ teaspoon black pepper
Sauté the Veggies: If the pot is dry, add a bit more oil. Sauté the onion and garlic for about 2 minutes, then add the carrots and celery. Cook for another 2 minutes until the onion softens.
1 medium onion, 1 tablespoon minced garlic, 2 celery stalks, 3 medium carrots
Thicken the Base: Sprinkle the flour over the vegetables and stir to coat. Slowly pour in the beef broth while stirring to prevent lumps.
4 tablespoons all-purpose flour, 2 ½ cups low-sodium beef broth
Build the Flavor: Add the wine (or beer), water, tomato paste, bay leaves, and thyme. Stir well, then return the browned beef to the pot.
1 ½ cups dry red wine or dark beer, 1 ½ cups water, 2 tablespoons tomato paste, 2 bay leaves, 1 teaspoon dried thyme
Simmer the Soup: Cover the pot and lower the heat to medium-low. Simmer gently for about 1 hour and 15 minutes, or until the beef is tender.
Add Final Veggies: Stir in the diced potatoes and frozen peas. Simmer uncovered for another 20 minutes, or until the potatoes are fully cooked. If using mushrooms, add them in the last 5 minutes.
2 medium potatoes, 1 cup frozen peas
Make the Mushrooms (Optional): In a separate skillet, melt the butter over medium-high heat. Add the mushrooms and cook for about 5 minutes until browned. Season lightly with salt and pepper, then stir into the soup.
1 tablespoon butter, 6 ounces mushrooms
Finish and Serve: Remove the bay leaves. Taste the soup and adjust the seasoning with more salt and pepper if needed. Ladle into bowls and serve with crusty bread or cheesy garlic toast.