Step 1: Heat 1 tablespoon of olive oil in a large pot or Dutch oven over medium heat. Add the chopped onion, carrots, and celery. Sauté for 5-7 minutes, until the vegetables begin to soften and become fragrant.
Step 2: Stir in the minced garlic, ground cumin, turmeric, and smoked paprika. Cook for another minute, stirring constantly, until the spices are fragrant. Be careful not to burn the garlic!
Step 3: Add the rinsed red lentils, canned diced tomatoes (undrained), and vegetable broth to the pot. Stir everything together. Add the bay leaf.
Step 4: Bring the soup to a boil, then reduce the heat to low, cover, and simmer for 15-20 minutes, or until the lentils are tender and have broken down, creating a creamy consistency. Stir occasionally to prevent sticking.
Step 5: Remove the bay leaf. Season the soup generously with salt and black pepper to taste. If you like a little brightness, stir in the juice of half a lemon.
Step 6: Ladle the hot soup into bowls. Garnish with fresh parsley or cilantro, and if desired, a dollop of plain Greek yogurt or a drizzle of olive oil. Serve immediately.