How to Make It
Preheat the broiler to 425° and position a rack 6 inches from the heat. Arrange the eggplant on a baking sheet and broil for 30 minutes, turning the eggplant every 10 minutes, until it is soft and charred in spots. When it is cool enough to handle, cut the unpeeled eggplant into chunks.
Meanwhile, 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 onion is medium brown, about 8 to 10 minutes. Add the ginger and garlic and cook for 1 minute. Add all of the spices and cook for about 30 seconds, stirring constantly.
Stir in the crushed tomatoes, and scrape the bottom of the pan to remove any browned bits. Add ¾ cup of water and the potatoes to the pan, reduce the heat to low and simmer the sauce slowly for about 15 minutes, until it thickens and the potatoes are soft. Add more water if the sauce thickens before the potatoes are cooked tender.
Stir in the eggplant and the peas and cook for 2 minutes.
Remove from the heat and allow the mixture to cool for a couple minutes, then stir in the heavy cream, if using. Season with sea salt to taste.
Basmati rice and naan, if desired.