2.5 pounds roast beef with marbleized fat throughout, cut into 2–3 inch chunks
Kosher salt and freshly ground black pepper to taste
3 Tablespoons tomato paste
5–6 cups mixture of water and lower-sodium beef broth (use half water, half broth)
1 Tablespoon olive oil (for vegetables)
2 medium leeks, white and light green parts only, chopped (about 2 cups)
2 stalks celery (1 cup), chopped
4 carrots (3 cups), chopped
4 cloves garlic, minced
1 medium cabbage (about 10 cups), chopped
15 oz. tomato sauce
7–8 cups lower-sodium beef broth
1 teaspoon thyme
1 Tablespoon Worcestershire sauce
3 bay leaves
Salt and pepper to taste
Instructions
Heat 2 tablespoons olive oil in large stockpot over medium-high heat. Season beef chunks liberally with salt and pepper. Brown on all sides using tongs, working in batches to avoid crowding, about 8-10 minutes total.
Remove beef to plate. Add tomato paste to pot, stir for 30 seconds, then add broth and water mixture. Deglaze pan by scraping up brown bits. Return beef to pot, bring to simmer, reduce heat to medium-low, and cover pot with lid slightly ajar. Cook for 1.5-2.5 hours, occasionally skimming foam or fat, until fork-tender.
Remove cooked beef to plate and shred with two forks when cool enough to handle. Reserve the cooking broth.
In same stockpot, heat 1 tablespoon olive oil over medium-high heat. Add leeks, celery, carrots, thyme, salt and pepper. Sauté until slightly softened, 4-5 minutes. Add garlic during last 30 seconds.
Add tomato sauce and 7-8 cups beef broth (can use reserved broth, but taste first as it is already seasoned) to pot and stir. Add chopped cabbage, Worcestershire sauce, and bay leaves.
Bring to boil, then reduce heat and simmer until cabbage is tender and wilted, about 15-20 minutes. Add shredded beef back to pot and heat through for 5 minutes. Remove bay leaves, adjust seasonings, and serve.
Notes
Use large stockpot and tongs for best results. Choose chuck roast with marbleized fat for most tender results. Always sear beef well and cook until fall-apart tender.
Can substitute leeks with one large yellow onion. Soup stores for 4-5 days refrigerated and freezes well for up to 3 months.
For slow cooker: sear beef first, then cook on high for 4 hours. For Instant Pot: sauté beef, add broth, pressure cook 50-60 minutes with slow release.
Add extra broth if soup becomes too thick during cooking or storage. The large amount of cabbage will reduce significantly as it wilts.