In a small to medium-sized soup pot, heat the olive oil over medium heat. Add the chopped onion, carrot, and celery. Sauté for about 3 minutes until the vegetables start to soften.
Add the minced garlic, ground cumin, smoked paprika, and a pinch of red pepper flakes. Stir and cook for another 1-2 minutes until the spices are fragrant.
Add the rinsed red lentils, water and diced tomatoes to the pot. Season with salt and black pepper to taste. Stir everything well. Bring the mixture to a boil, then reduce the heat to low, cover the pot, and let it simmer for about 15-20 minutes, or until the lentils and vegetables are tender. Stir occasionally.
Once the lentils and vegetables are tender, stir in the chopped spinach or kale and let it wilt in the hot stew.
Reduce the heat to low and add the heavy cream or coconut milk to the stew. Stir until the stew becomes creamy and well combined. Adjust the seasoning if needed. Simmer the stew for an additional 5 minutes to heat through. Serve your creamy red lentil stew hot, garnished with fresh parsley or cilantro and enjoy!