Kidney beans curry

Very tasty with rice and naan and very very easy too.
Ingredients
1 cup Rajma/Red Kidney Beans (soaked overnight/8 hours)/ 2 cans of cooked kidney beans
½ cup finely chopped onions
1 teaspoon chopped ginger
1 cup chopped tomatoes
1 teaspoon cumin seeds
1 teaspoon turmeric powder
1 teaspoon cumin powder
1 teaspoon garam masala powder
1 tablespoon butter
2 tablespoons chopped coriander leaves
1 teaspoon Vegetable/Sunflower Oil
Salt to taste
Method
Cook the soaked rajma in about 3 cups of water in a pot or a pressure cooker until the rajma is soft, tender and cooked. Takes about 20 to 30 minutes, depending on the age of the beans.
Heat oil to a sauce pan, add chopped ginger and onions. Sauté until onions are soft and golden brown.
Add chopped tomatoes, turmeric powder, cumin powder, garam masala powder and sauté until tomatoes become soft.
Add the cooked rajma , salt, 1 cup water and butter and simmer for 30 minutes. The longer you simmer the more the spices get into the rajma and the tastier it gets. You can alter the consistency of the gravy by adding more water.
Garnish with coriander leaves and serve hot with warm long grained rice.