Lentil Soup Recipe

Heat the olive oil and melt the butter in a large pot or Dutch oven over medium heat. Add the onions and cook, stirring often, for 4-6 minutes or until soft and translucent. Add the carrots and celery and mix well to combine with the onion. Continue to cook over medium heat for 10 minutes, stirring often. Do not rush this process.
Reduce the heat to medium-low and add the minced garlic. Cook, stirring continuously, for approximately 1 minute, then add the salt, dried thyme, basil, and sweet paprika. Mix well to combine.
Rinse the lentils under cool water. Add the diced tomatoes, vegetable broth, and lentils to the pot. Stir well to combine. Increase the heat to high and bring it to a simmer. As it simmers, you may notice some frothy scum float to the surface. Use a spoon or ladle to scoop it off the surface and discard. (Note: you may need to do this 1-2 more times throughout cooking)
Cover and reduce the heat to medium-low. Simmer, stirring occasionally, for 40-60 minutes or until the lentils are soft.
Blend the soup (optional). For a thicker, more incorporated soup, use an immersion blender to blend the soup until the desired consistency is reached. You may also transfer all (or part) of the soup to a high-speed blender and blend until processed.
Stir in the lemon juice and zest just before serving. Mix well to combine—season with additional salt and pepper to taste. Serve in serving bowls with fresh parsley, shredded parmesan, and sour cream.