Sauté the Vegetables: Heat olive oil in a large pot over medium heat. Add the diced onion and carrot, cooking for about 5 minutes until softened. Add the garlic and cook for an additional 30 seconds, just until fragrant.
Add the Spices: Stir in cumin, coriander, and turmeric. Let them toast in the oil for about 1 minute to release their aromas and deepen their flavor.
Combine Lentils and Tomatoes: Add the rinsed red lentils and diced tomatoes (with their juices) to the pot. Stir to combine with the spices
Pour in Broth: Add vegetable broth to the pot and stir. Bring the mixture to a boil, then reduce the heat and simmer for 25-30 minutes, or until the lentils are tender and have absorbed much of the liquid. Stir occasionally.
Blend for Smoothness: Once the lentils are fully cooked and tender, use an immersion blender to blend the soup to your desired consistency. You can blend it all for a creamy texture or leave some lentils whole for added texture.
Season and Finish: Stir in the lemon juice and season with salt and pepper to taste. Top with freshly chopped cilantro for a burst of freshness.
Serve: Ladle the soup into bowls and serve hot. Garnish with extra cilantro if desired. Enjoy with a slice of crusty bread for the perfect meal!