Heat the olive oil in a large pot, add the onion and carrots, and cook for about 5 minutes until they begin to soften.
Stir in the garlic, cumin, and smoked paprika, then cook for 30 seconds to release their aroma.
Add the rinsed lentils, diced tomatoes, vegetable broth, salt, and black pepper.
Bring the mixture to a boil, reduce the heat, and simmer uncovered for 20 to 25 minutes until the lentils are tender.
Blend part of the soup for a thick but textured consistency, or blend the entire pot until completely smooth.
Stir in the lemon juice and add a little extra broth if the soup has become thicker than preferred.