Olive oil or vegetable cooking spray
2 Tablespoon clarified butter or canola oil
2-Inches fresh ginger, cut into thin matchsticks
1 Onion, sliced in half and then cut into 1/4-inch half moon slices
1 Clove garlic, minced
1/2 Small Serrano or Thai chile, seeded and minced
1/8 Teaspoon crushed red chili flakes
1/4 Teaspoon turmeric
3/4 Teaspoon cumin seeds
2 Teaspoons ground coriander
1/2 Teaspoon garam masala
1/2 Teaspoon mango powder (amchur)
1 Head cauliflower, broken into 1/2 pieces
1/2 Teaspoon Kosher salt
1/4 Teaspoon freshly ground black pepper
1/2 Cup water
1/4 Cup fresh cilantro leaves

Preheat oven 400F. Oil or spray a 13x9-inch casserole dish or baking sheet.
Heat the clarified butter in a 12-inch skillet over medium heat. Add onions, cover and cook until softened, for about 5 minutes. Add the ginger, garlic and pepper and cook until fragrant, about 30 seconds. Add red chile flakes, turmeric, cumin seeds, coriander, garam masala, and mango powder. Cook an additional 30 seconds. Add the cauliflower, salt, pepper and water and cook an additional 3-4 minutes, stirring occasionally. If the curry becomes dry add a few tablespoons water.

Put the cauliflower into the prepared casserole dish and roast for 30 minutes, or until tender. Garnish with cilantro leaves and serve.