Heat olive oil in a large pot over medium heat.
Add chopped onions and sauté until translucent.
Stir in diced carrots and potatoes; cook for about 5 minutes.
Mix in ground cumin and paprika; cook for 1-2 minutes until fragrant.
Add rinsed red lentils and stir to combine.
Pour in the vegetable broth and bring to a boil.
Reduce heat and simmer for 25–30 minutes until lentils are soft.
Blend the soup with an immersion blender until smooth.
Season with salt, pepper, and fresh lemon juice.
Serve warm, garnished with additional lemon if desired.