Bring two cups water to a boil. Once it's boiling, add in brown rice, quinoa, and ½ tsp saffron threads. Stir and lower heat (to lowest setting) and let the rice mixture cook.
Preheat oven to 350 degrees. Puree tomatoes, chopped onion and chiles to taste in a food processor, scraping down the sides as needed, to make a smooth sauce.
Heat 2 teaspoons oil in a large skillet over medium-high heat. Add raisins and cashews and cook, stirring, until the raisins are plump and the nuts are lightly brown, 1 to 3 minutes. Transfer to a plate.
After you take out the raisins/cashews, add about 2-3 tsp oil in the skillet. Add cumin seeds, cardamom pods, bay leaves and cinnamon sticks to the pan and cook, stirring, until fragrant, 30 seconds to 1 minute. Add the sliced onion and cook, stirring, until light brown, 2 to 3 minutes.
Pour in the pureed tomato mixture (it may spatter) and reduce heat to medium. Stir in garam masala, 3/4 teaspoon salt and turmeric. Simmer, partially covered, stirring occasionally, until most of the liquid evaporates, about 15 minutes.
Stir spinach, cauliflower, chickpeas and up to 1 cup water into the tomato sauce. Cover and remove from the heat.
Lightly coat a 9-by-13-inch baking dish with cooking spray.
Spread half the chickpea curry evenly in the prepared baking dish. Spread the rice mixture on top of the curry. Spoon the remaining chickpea mixture over the rice. Scatter the reserved raisins and cashews over the top. Cover with foil. Bake until the rice is tender, ~35 min. Remove the bay leaves, cardamom pods and cinnamon sticks before serving.