from Mark Bittman's How to Cook Everything Vegetarian
He has like 72 different things you can serve this with -- the fresh cheese and chickpea dish I semi-used it for, cubes of fried tofu, dipping sauce for flatbread with potato or dosa, etc. etc.
Makes 2 cups.
4 T butter or 1/4 c neutral oil, like grapeseed or corn
1 medium onion, chopped
2 cloves garlic, minced
one 1-inch piece ginger, peeled and minced
1 T minced fresh chile or hot red pepper flakes or cayenne to taste
2 T garam masala or curry powder
1/2 t chili powder
large pinch sugar
2 c chopped ripe tomato (about 1 lb. whole), preferably peeled and seeded, or drained canned tomatoes
1/2 cream or coconut milk
1/2 c chopped fresh cilantro leaves
1 t cumin seeds
1 t mustard seeds
1. Put 3 T of the butter or oil in a deep skillet over medium0-high heat. When the butter is melted or oil is hot, add onion, garlic, ginger and chile. Cook, stirring occasionally, until onion is soft, about 5 minutes. Stir in garam masala, chili powder and sugar and sprinkle with salt and pepper; cook and stir until spices become fragrant, a minute or two more.
2. Add tomato and cook, stirring frequently, until it starts to release its liquid, about 3 minutes. Add the cream and cilantro and keep cooking and stirring until the mixture comes to a boil.
3. Turn heat down so the sauce bubbles gently and cook, stirring occasionally, until the tomato breaks up and the mixture comes together and thickens, about 30 minutes. Taste and adjust seasoning. (The sauce may be made ahead to this point, cooled, covered and refrigerated for up to 3 days. Reheat gently before proceeding.)
4. Put remaining butter or oil in a small pan over medium-high heat. When the butter is melted or the oil is hot, add cumin and mustard seeds and toast them until they begin to pop. Spoon over the sauce just before serving.