Sauté the vegetables: Heat the olive oil in a large pot over medium heat. Add the onion, red pepper, garlic, and carrot. Cook until softened and fragrant, about 5-6 minutes.
Add the spices: Stir in the cumin, chilli powder, smoked paprika, ground coriander, and tomato paste. Cook for another 1-2 minutes, allowing the spices to release their aromas.
Add the lentils and liquid: Add the red lentils, vegetable broth, diced tomatoes, and kidney beans. Stir well to combine.
Simmer: Bring the mixture to a low boil, then reduce the heat and simmer for 20-25 minutes, stirring occasionally, until the lentils are tender and the chilli has thickened.
Season and serve: Taste and season with salt and pepper as needed. Serve with your favourite toppings, such as avocado slices, fresh coriander, or a squeeze of lime for extra freshness.