Prep the Ingredients: Chop the cauliflower into bite-sized florets, roughly chop the spinach, finely chop the onion, and mince the garlic and ginger.
Sauté the Aromatics: Heat the vegetable oil in a large pan over medium heat. Add the chopped onion and sauté until translucent, about 5 minutes. Add the minced garlic and ginger, cooking for another 2 minutes until fragrant.
Add the Spices: Stir in the curry powder, ground cumin, ground turmeric, garam masala, and red chili powder. Cook for 1-2 minutes, stirring constantly to avoid burning the spices.
Add Tomatoes and Cauliflower: Add the diced tomatoes and their juice to the pan, stirring well to combine. Add the cauliflower florets, stirring to coat them with the tomato and spice mixture.
Simmer the Curry: Pour in the vegetable broth and coconut milk, bringing the mixture to a gentle simmer. Cover the pan and let it cook for about 15 minutes, or until the cauliflower is tender.
Add Spinach: Stir in the chopped spinach, allowing it to wilt into the curry, about 2-3 minutes. Season with salt to taste and top with chopped coriander.