In a large pot, heat the olive oil over medium heat. Once hot, add the chopped onion, carrots, and celery. Sauté for about 5 minutes or until the vegetables start to soften.
Add the minced garlic, ground cumin, and smoked paprika to the pot. Stir frequently for about 1 minute until the garlic is fragrant.
Add the diced potatoes and rinsed lentils to the pot, stirring everything together until the lentils and potatoes are well-coated with the spices.
Pour in the vegetable broth and add the bay leaf. Bring the mixture to a boil, then reduce the heat to a simmer.
Cover the pot and let it simmer for about 30-35 minutes, or until the lentils and potatoes are tender. Stir occasionally, and add more broth or water if needed to maintain your desired soup consistency.
After cooking, remove the bay leaf and season the soup with salt and pepper to taste.
For an extra creamy texture, you can use an immersion blender to blend a portion of the soup directly in the pot, or blend a few cups in a regular blender and return it to the pot.