- In a large skillet over medium-high heat, brown the onion in the oil. Add the ground beef and garlic. Cook breaking the meat up with a wooden spoon until golden. Add the spices and cook for 1 minute while stirring. Add the remaining ingredients and cook until the mixture is almost dry. Season with salt and pepper. Keep warm.
- In a bowl, combine the tomatoes, cilantro and lime juice. Season with salt and pepper.
- When ready to serve, divide the beef and lentil mixture among the taco shells. Top with the cheese, lettuce, sour cream and tomato mixture.