Step 1
Melt the butter or ghee in the oil in a large Dutch oven set over medium heat, and when it is hot and shimmering, add the cumin seeds and cinnamon sticks. Cook for a minute or two, stirring often, to intensify their flavors, then add the onions. Cook, stirring occasionally, until they are golden, approximately 15 to 20 minutes.
Step 2
Meanwhile, put the ginger, garlic and peppers into a mortar and pestle with a pinch of salt, and smash them together into a coarse paste. (You can also do this on a cutting board, with a knife.)
Step 3
Add the paste to the onions, and cook for 2 minutes or so, then pour in the tomatoes, and stir. Allow to cook for an additional 2 to 3 minutes,ground cumin, ground turmeric and another pinch of salt, and stir to combine.
Step 4
Melt the butter or ghee in the oil in a large Dutch oven set over medium heat, and when it is hot and shimmering, add the cumin seeds and cinnamon sticks. Cook for a minute or two, stirring often, to intensify their flavors, then add the onions. Cook, stirring occasionally, until they are golden, approximately 15 to 20 minutes.