Sour cream, sliced red onion and additional paprika
In a large skillet, heat oil over medium-high heat. Add onion; cook and stir until tender, 4-5 minutes. Add lentils and garlic; cook 1 minute longer. Transfer to a 5- or 6-qt. slow cooker. Stir in carrots, broth and seasonings. Cook, covered, on low until vegetables and lentils are tender, 4-6 hours.
Stir in diced tomatoes; cook, covered, 30 minutes longer. Serve with avocados and if desired, sour cream, red onion and additional paprika.
Freeze Option: Freeze cooled chili in freezer containers. To use, partially thaw in refrigerator overnight. Heat through in a saucepan, stirring occasionally and adding a little broth or water if necessary.