Melt butter in a large saucepan over medium heat. Add ginger, garlic, and onion and stir-fry for 1 minute. Add turmeric and chile powder. Mix well. Add corn and tofu. Mix well and continue to cook for 1 minute. Add water and milk. Continue to stir until soup comes to the boil. Lower heat and simmer for 5 minutes.
Remove from heat and serve hot, garnished with green onions if desired.
Source: 'The Kopan Cookbook'