Sear the beef – Heat olive oil in a large pot over medium heat. Add beef and brown on all sides. If using ground beef, break it into small pieces while browning.
Cook vegetables – Add onions, garlic, carrots, and celery. Sauté until softened, about 5–7 minutes.
Add spices – Sprinkle in cumin, smoked paprika, and thyme. Stir for 1 minute to release the aroma.
Add lentils and liquids – Pour in lentils, diced tomatoes, and beef broth. Stir well. Bring to a boil, then lower heat and simmer, covered, for 25–30 minutes or until lentils are tender and beef is cooked through.
Adjust seasoning – Add salt and pepper to taste. For thicker soup, mash a few lentils against the side of the pot.
Serve – Ladle into bowls, sprinkle with fresh parsley if desired. Serve hot with bread if you like.
