Dice the onion and mince the garlic. Sauté both in a large pot with olive oil over medium heat until softened. Dice the celery while the onions and garlic are sautéing, then add to the pot and continue to sauté for 2-3 minutes more.
Add the cumin, turmeric, cinnamon, and cayenne pepper to the pot. Stir and cook the spices with the vegetables for 1-2 minutes.
Add the diced tomatoes (with juices), chickpeas (rinsed and drained), and cauliflower florets (no need to thaw). Stir the pot until everything is well mixed.
Add the vegetable broth and bay leaf, turn the heat up to high, place a lid on the pot, and allow it to come to a boil. Once it reaches a boil, add the lentils. Stir and let it come back up to a boil, then turn the heat down to low. Let the stew simmer on low, with the lid, for 30 minutes.
After simmering for 30 minutes, the lentils should be tender. Remove the bay leaf and give the stew a taste. Add salt if needed (this will depend on the type of vegetable broth used. I did not add any additional salt), then serve.
*I use Better Than Bouillon soup base to make my broth.