Heat the ghee in a skillet over medium heat. Add the onion and ginger and cook for 1 minute. Add the mango, raisins, sugar, tamarind paste, and curry powder. Season with salt and pepper, reduce the heat to low, and cook until everything is soft and the flavors have blended, about 30 minutes. Put the chutney into a bowl and allow it to cool before serving.
Put the butter in a heavy saucepan over medium-low heat. Melt the butter slowly and make sure it does not sizzle or brown. Increase the heat and bring the butter to a boil. When the surface is covered with foam, stir gently and reduce the heat to the lowest possible setting. Gently simmer, uncovered, and undisturbed for 45 minutes, until the milk solids in the bottom of the pan have turned golden brown and the butter on top is transparent. Strain the ghee through a sieve lined with several layers of cheesecloth. The ghee should be perfectly clear and smell nutty; pour into a glass jar and seal tightly.
Toast the coriander, cumin, cardamom, peppercorns, fennel, mustard, cloves, and the chiles in a small dry skillet over medium-low heat just until they smell fragrant, about 2 minutes. In a clean coffee grinder or spice mill, grind the toasted spices together to a fine powder. Add the turmeric and give it another quick buzz to combine. Use the curry powder immediately, or store in a sealed jar for up to 1 month.