Prepare Beef
Shred or cube leftover pot roast. If using raw beef, cook in a slow cooker until tender and fall-apart before starting soup.
Sauté Vegetables
Heat olive oil in a large pot over medium heat. Add onion and carrots. Cook 5–7 minutes until softened. Add garlic and cook 30 seconds until fragrant.
Build the Soup
Add potatoes, cooked beef, and broth (or water + bouillon). Stir in tomato sauce and 2 cans of water.
Add Remaining Ingredients
Add peas, green beans, basil, Italian seasoning, salt, and pepper. Stir to combine.
Simmer
Bring to a boil, then reduce heat and simmer 30–40 minutes until potatoes are tender.
Taste & Serve
Adjust seasoning as needed and serve hot with homemade bread.