How to Make It
In a large frying pan, heat the oil or ghee over medium high heat. Add the onion and 1 teaspoon of sea salt and cook, stirring occasionally, until the onions are medium brown, about 8 to 10 minutes. Add the ginger and garlic and cook for 1 minute more. Add all of the spices and cook for about 30 seconds, stirring constantly.
Stir in the crushed tomatoes, scraping the bottom of the pan to remove any browned bits. Add 1/2 cup of water to the pan, reduce the heat to low and slowly simmer for about 15 minutes, or until the sauce thickens and begins to splatter.
Remove from the heat and allow the curry to cool for a couple minutes, then stir in the heavy cream, if using. Season it with sea salt to taste.
Basmati rice and naan if desired.