.Combine broth and 1 1/2 cups water (if using broth, just use 5 1/2 cups total) in a 4 1/2 quart Dutch oven or soup pot and bring to a boil over high heat.
Meanwhile, pick through the lentils to check for stones or debris. Rinse and drain the lentils.
when the broth comes to a boil, add the lentils and return to a boil.
Reduce heat to low, cover, and slow boil for 20 minutes. If it starts to boil over, partially uncover.
Add tomatoes with juice. Peel and coarsely chop the onion and add to pot. Add garlic, tomato paste, ketchup, chili powder, cumin, thyme, salt, and black pepper. Stir to mix well.
Simmer, uncovered, stirring frequently for 15 minutes. Add a little more water or vegetable stock if moisture evaporates.
Remove the pot from heat and stir in oil and vinegar. Add hot sauce and pepper to taste.
Serve right away topped with cheese and sour cream.