Heat the oil: In a large pot, warm the olive oil over medium heat.
Sauté veggies: Add the diced carrots, onion, and celery to the pot. Cook until the onion is soft and clear, about 5-6 minutes.
Add flavor: Stir in the minced garlic and cook until fragrant, around 30 seconds. Mix in the balsamic vinegar, smoked paprika, cumin, cayenne, and red lentils.
Simmer the stew: Pour in the vegetable stock and season with salt and pepper. Bring to a simmer, then partially cover the pot. Let it cook until the lentils are tender, about 7-10 minutes.
Finish with lemon: Take the pot off the heat and stir in the fresh lemon juice.
Serve and enjoy: Dish out the stew hot, topped with your choice of fresh herbs.