Basic Curry Sauce

Coarsely chop the onion. Heat oil and margarine together over medium-high heat in large pan (a wok is good). Cook the onion until it's very brown. Add the minced ginger and garlic to the onion and cook for an additional 2 minutes.

Process onion/ginger/garlic mixture in a food processor until smooth. Return mixture to stove - at this point it might be good to switch from the wok to a large saucepan.

Add all the spices and cook over low heat. Add a little water if necessary to mix in the spices, but the mixture should be thick like a paste.

Puree the tomatoes and peppers in the food processor until smooth. Add to onion mixture and stir well over low heat to cook off excess moisture. Add 1/2 cup yogurt a little at a time, stirring constantly to avoid curdling. Add the water, increase heat to high, and bring to a rolling boil. Cover the pot and boil for 3-5 minutes, then reduce heat and cook until you've reached the desired texture. Add salt if desired.

If serving with meat or vegetables, cook the meat or vegetables first, then simmer in the sauce for 5-10 minutes before serving.