Sauté the aromatics: In a large pot, heat olive oil over medium heat. Add the chopped onion, carrots, and celery. Sauté for 5-7 minutes until softened. Stir in the garlic and cook for another minute until fragrant.
Add spices and base ingredients: Sprinkle in the cumin, smoked paprika, thyme, salt, and black pepper. Stir well. Add the lentils, diced potatoes, and diced tomatoes (with juices). Mix to coat everything in the seasoning.
Simmer the soup: Pour in the vegetable broth and add the bay leaf. Bring the soup to a boil, then reduce heat and let it simmer for about 30-35 minutes, or until the lentils and potatoes are tender.
Finish with flavor: Stir in the lemon juice for a touch of brightness. Taste and adjust seasoning as needed.
Serve and enjoy: Remove the bay leaf, ladle the soup into bowls, and garnish with fresh parsley. Serve with crusty bread for a complete meal!
