In a large 11-inch (28 cm) casserole pot, heat 2 tablespoons vegetable oil over medium heat. Add the chopped onion and sauté until it begins to brown. Stir in 1 tablespoon minced garlic and cook for about 1 minute, or until fragrant.
Add the ground chicken to the pot. Season with 1 teaspoon cumin powder, 1 teaspoon paprika, and 1 teaspoon onion powder. Cook over medium-high heat for about 5 minutes, stirring occasionally, until the chicken is browned. It does not need to be fully cooked at this stage.
Add the quartered mushrooms, season with ½ teaspoon salt and ½ teaspoon black pepper, and cook for another 2–3 minutes.
Stir in 1 cup diced celery, 5 cups baby potatoes (quartered), 6 cups chicken stock or broth, and 2 bay leaves. Cover the pot and cook for 10–12 minutes, or until the potatoes are tender.
In a small bowl, whisk together 1 cup heavy cream and 2 tablespoons flour until smooth. Pour the mixture into the pot and bring to a gentle boil. Let it cook until the broth thickens. Alternatively, you can mash a few potatoes in the pot to help thicken the soup.
Taste and adjust salt and pepper as needed. Add 4 cups baby spinach, cover with the lid, and reduce the heat to low. Let the spinach wilt for a few minutes before serving.
Serve hot with naan bread. Enjoy!