Prepare the ingredients by rinsing the lentils, dicing the vegetables, and mincing the garlic.

In the slow cooker, combine the lentils, carrots, celery, onion, garlic, potato, and canned diced tomatoes.

Pour in the halal vegetable broth and stir to mix the ingredients evenly.

Add the ground cumin, smoked paprika, ground turmeric, dried thyme, bay leaf, salt, and black pepper. Stir to combine the spices with the mixture.

Drizzle the olive oil over the soup mixture and give it a final stir.

Cover the slow cooker with its lid and cook on low heat for 6-8 hours or on high heat for 3-4 hours, until the lentils and vegetables are tender.

Once the soup is cooked, discard the bay leaf and taste for seasoning. Adjust the salt and pepper if needed.

Serve the soup warm in bowls. Optionally, drizzle with lemon juice and garnish with chopped fresh parsley for added brightness.