Prepare Lentils: Rinse the lentils under cool running water to remove any impurities, then drain well and set aside for later use.
Sauté Vegetables: In a large, heavy-bottomed pot, heat the olive oil over medium heat. Add the chopped onion and minced garlic, stirring frequently. Once fragrant, toss in the diced carrot and celery. Cook for about 5–7 minutes, or until the vegetables are softened and aromatic.
Add Seasonings: Sprinkle in the smoked paprika, ground cumin, dried thyme, salt, and a generous pinch of black pepper. Stir well to evenly coat the vegetables in the spices. Allow the mixture to cook for 1–2 minutes, releasing the flavors.
Combine Ingredients: Pour in the diced tomatoes and broth, then add the rinsed lentils. Mix thoroughly to ensure everything is well combined.
Simmer: Raise the heat to bring the mixture to a gentle boil. Once boiling, lower the heat to a simmer and cover the pot with a lid. Let it cook for 25–30 minutes, stirring occasionally to prevent sticking, until the lentils are tender and the flavors have melded beautifully.
Adjust Consistency: If the stew appears too thick, stir in a bit of additional water or broth to achieve your preferred texture.
Serve: Ladle the hearty lentil stew into bowls and garnish with fresh basil leaves, if using. Serve warm, alongside crusty bread or your favorite side for a comforting, wholesome meal.