1. Add the cinnamon, ground coriander, turmeric, paprika, garam masala, ground cumin and chilly powder together and lightly toast them on a hot griddle or frying pan. Keep the heat low and keep stirring with a wooden spoon until
you get the fragrance of the spices. Remove the mixture in a bowl and allow to cool. Prepare the Onions ,ginger and garlic. Chop the onions in slices, the garlic in small pieces and grate the ginger, In a saucepan, add the oil and mustard seeds. Once the mustard
seeds pop, add the curry leaves, onions, ginger and garlic. Keep stirring and make sure the garlic doesn't get burnt or it will ruin the taste of the sauce.
3. Once the onions are cooked, add the spice mixture to the onions and lower the heat.
4. Now add the tomatoes with one cup of hot water. Also add the salt, lemon juice and cardamom seeds and allow this to simmer on a low heat.
5. Once the sauce looks rich and thick, take it off the heat and allow to cool.
6. Once cooled, remove the curry leaves and blend the sauce to make it smooth.