Eggplant with Potatoes (Bangon Aloo)

3/4 lb. eggplant
1/2 lb. potatoes
1/3 cup sliced onion
1/2 tsp cumin seeds
1/2 tsp roasted and crushed coriander seeds
1 tsp grated ginger root
4-5 cloves garlic, finely chopped
1/2 tsp chili powder
1/4 tsp tumeric
1 tbsp nonfat yogurt
1/2 tsp sugar
1-2 green chilis, chopped
1/3 cup chopped tomato
1 tbsp lemon juice
2 tbsp chopped cilantro leaves

Wash the eggplant. Cut it into quarters lengthwise, then, holding the pieces together, cut them across into 1/2 inch chunks. Scrub the potatoes thoroughly and don't peel them. Cut into quarters and cut quarters twice so you get 12 bite size pieces from each tater. Very slowly dryfry onion until it turns light brown (slowly carmelizing the onions)Add cumin and coriander seeds, stir for a minute, then add ginger, half garlic, chili powder, tumeric and cook over very high heat, adding a couple of tablespoons of water as necessary to keep the spice paste from sticking. Spices should deepen in color, this should not take more than two minutes. Add eggplant, yogurt, sugar, and green chilis. Mix all togetherand cook 2-3 minutes. Add 2/3 cup of water, lower heat and and simmer 15 minutes, with lid firmly on. Add taters, peppers, and tomatoes. Make sure lid is very tight, simmer another 10 minutes, checking occassionally so it is not burning or sticking.. If too dry, add a bit more water. Lastly, add cilantro, garlic, and lemon juice, cook 1 more minute, gently stir to mix, then turn off heat.