Eggplant in Tahini and Mustard Sauce

I love eggplant, and mustard, and tahini, but I don't know that I'd ever had them together before. This unusual recipe from ecurry may not look the best (at least in the only snapshot I got of it before it was all eaten), but it's really delicious.

Does anyone have a good mustard oil to recommend? It's illegal to sell it for food uses in the US, and I'm a little wary of buying something that says it's a massage oil or aromatherapy oil, even if that is just a workaround. I've cooked with it before when I was house-sitting, and it was delicious! I'm sure it would really improve this recipe, too, though it was good with canola oil anyway.

Eggplant in Tahini and Mustard Sauce
(from ecurry)

Ingredients
4 medium Chinese/Asian eggplants or 1 large American Eggplant (about 8-10 inches long)
4 tablespoon oil pure mustard oil of any cooking oil +( 1 more tablespoon of pure virgin mustard oil – optional)
1/2 teaspoon kalonji/nigella seeds
6 hot green chilli peppers (more or less, adjust to taste) – slit
salt to taste
1 teaspoon turmeric powder
1 tablespoon Kashmiri Red Chili Powder (or cayenne or paprika) – adjust amount to taste
2.5 tablespoon yellow mustard seeds (or black for stronger flavors);  I have used a mix of both
2.5 heaped tablespoon Tahini (or Sesame Paste) (recipe for easy Homemade Tahini)
1 teaspoon sugar (not to make it sweet; just for the balance of taste)
about 1/4 cup water to make the paste + more water as needed for the sauce

Instructions
Wash the eggplant and pat dry. Slice them 2 inches long (about 3/4 inches wide) or in cubes. Sprinkle some salt and half a teaspoon of turmeric and toss well. Allow the eggplant to sit/sweat for about 10 minutes.

Make a paste with the mustard seeds and 1/4 cup water. Whisk in the sesame paste/tahini  and red chili powder, the rest of the turmeric and the sugar with the mustard paste and set aside. (If you do not have tahini, use lightly toasted sesame seeds along with the mustard seeds to make a mustard sesame paste).

Heat half of the oil in a pan (save the spoonful to drizzle). Add the nigella seeds and some of the slit chilli peppers (remove seeds and membrane carefully from the peppers if you do not want the heat; the fresh flavor is vital here). As the seeds sizzle and the peppers have brown blisters, add the eggplants and increase the heat.

Cook the eggplants while tossing frequently until they start to soften and brown. Most of the oil will have been absorbed by the eggplants. They would be about half cooked. Now add the rest of the oil, except the spoonful to drizzle and add the mustard tahini paste to the pan and toss everything together.

Cook at medium – low heat while gently stirring, preventing the paste from sticking to the bottom of the pan. Cook for about 3-5 minutes until the raw taste of the mustard and sesame is gone. Add about a cup (or maybe a little bit more depending on how much sauce you want) of water, give it a gently stir and partially cover to cook until the eggplants are done. The sauce should thicken and be able to coat the eggplants and have some extra.

Adjust salt. Finish of with a drizzle of pure mustard oil and more chili peppers if you want.

Serve hot over rice or with any flat breads.

Serves 4-6 as side