Sauté Aromatics: In a medium-large saucepan or Dutch oven, warm the extra virgin olive oil over medium heat. Add the finely chopped sweet onion and minced garlic. Cook, stirring occasionally, for 1 to 2 minutes until the aromatics are softened and fragrant, but not browned.
Toast Spices: Introduce the ground cumin, turmeric, ground coriander, sweet paprika, and ground cinnamon to the pot. Stir continuously for 3 to 4 minutes, allowing the spices to toast and become deeply aromatic.
Cook Carrots: Add the chopped carrots to the spiced aromatics. Continue to sauté, stirring periodically, for 8 to 10 minutes, or until the carrots have softened slightly.
Combine Ingredients: Pour in the low-sodium vegetable broth and the undrained diced tomatoes. Add the thoroughly rinsed red lentils and the dried bay leaf. Stir all the components together to ensure they are well combined.
Simmer Soup: Increase the heat to bring the mixture to a gentle simmer. Once simmering, reduce the heat to low, cover the saucepan, and allow the soup to cook for 18 to 22 minutes. Stir from time to time to prevent sticking, until the red lentils are completely tender and cooked through.
Blend (Optional): After the cooking time, carefully remove and discard the bay leaf. For a creamier texture, you can use an immersion blender to partially or fully blend the soup directly in the pot. Alternatively, for a smoother result, you can very carefully transfer a portion (or all) of the soup to a standard blender (ensure the lid is vented and covered with a towel to avoid splashes from hot liquid), blend until smooth, and then return it to the saucepan. If a chunkier texture is preferred, this step can be skipped.
Season: Taste the soup and adjust the seasoning with fine sea salt and freshly ground black pepper as desired.
Serve: Ladle the warm soup into individual serving bowls. Offer with a garnish of freshly chopped cilantro or Italian parsley, a wedge of lemon for squeezing, and a drizzle of fresh orange juice, if using, for an extra touch of brightness.