Shrimp Curry with Chilies and Cream

I got this recipe at an Indian Cooking Class that I took at a local gourmet grocery store. I've made it several times and everyone that has tried it has liked it.

Ingredients:
4 Tbsp of ghee, butter or canola oil
1 yellow onion, peeled, quartered and sliced
1 bunch of scallions, trimmed and sliced
1-2 garlic cloves, peeled and crushed
2 fresh green chilies, seeded and finely chopped or sliced (I used poblano peppers)
1-2 inch piece fresh ginger root, peeled and finely chopped
1 tsp ground turmeric
1 tsp ground cumin
1 tsp ground coriander
1 1/2 tsp curry powder
1 14oz can of chopped/diced tomatoes
2/3 cup of water
2/3 cup heavy cream or coconut milk or combination of the two
1 lb of raw shrimp, diced chicken, tofu or other meat
2 Tbsp chopped fresh cilantro

Heat the ghee/oil in a pan and fry the onions, scallions, garlic and chilies over medium heat for 3 minutes. Stir in the ginger, spices and curry powder and cook for 1 more minute. Stir in the tomatoes and water and bring to a boil, stirring. Reduce the heat and simmer for 10 minutes, stirring occasionally. Add the cream and simmer for 5 more minutes. Add the shrimp and cilantro and season with salt to taste. Cook for 2-3 minutes, until the shrimp are pink. Adjust the seasoning if necessary. Serve with fruity pulao rice.