Heat olive oil in a large pot or Dutch oven over medium heat. Add sliced onions and a small pinch of salt. Cook for 15–20 minutes, stirring occasionally, until deeply caramelized and golden brown.

Add minced garlic, ground cumin, and smoked paprika. Stir for 1–2 minutes until fragrant.

Add diced carrots and cook for 5 minutes until slightly softened.

Stir in red lentils, vegetable broth, and diced tomatoes. Bring to a boil.

Reduce heat to low, cover, and simmer for about 20 minutes, or until lentils are tender.

For a smoother Caramelized Onion Red Lentil Soup, blend with an immersion blender to your desired consistency. Leave slightly chunky if preferred.

Stir in salt, black pepper, and lemon juice. Taste and adjust seasoning.

Serve hot, garnished with fresh parsley or cilantro if desired.