Bring the vegetable stock to a simmer in a saucepan over medium heat. Turn to low and keep hot.
Melt 4 tablespoons butter in a large saucepan. When it begins to foam, add the onions and cook until soft, about 3 minutes. Add the dried curry leaves, garam masala, cardamom pods, mustard seeds and star anise, and continue to cook for 1 minute. Stir in the mushrooms and cook until they begin to caramelize, about 5 minutes. Add the rice, stirring so it is well coated with the butter, and then add the wine, stirring constantly as it is absorbed into the rice.
Begin to add the hot stock a little at a time and continue to stir constantly as it is absorbed into the rice. The rice is done when it is tender and creamy in consistency, about 30 minutes. Turn off the heat and stir in the remaining 3 tablespoons butter and season with salt.
Spoon the risotto into wide, shallow bowls and garnish with Parmigiano-Reggiano shavings and a scattering of dried chilies.