In a large sauté pan over medium heat, sauté onions, garlic, and ginger until translucent . Add spices and stir through. Add honey and the tomatoes to the pan. Add the cauliflower and chickpeas and let simmer until the cauliflower has softened and cooked through and reduced a bit about 10-15 minutes. Season with salt and pepper and finish with cilantro and lemon zest.
In a skillet over medium heat, heat the vegetable oil. Build the sandwich with the cheese, vegetable mixture and the top slice of Naan and sear on both sides pressing down with a grill press or you can use a panini maker. Remove from pan and slice in half . Serve with the mango relish.