Salt eggplant and leave it in a colander for at least 15 minutes. Squeeze out the excess water, pat dry on a clean kitchen towel and keep ready.
Heat oil in a saute pan, add the onions, peppers, mushrooms, garlic and the eggplant. Cook the veggies for 4~5 minutes or until the onions are soft and the other veggies start to get tender. Lower the heat, cover the pan and cook till the veggies are tender.
Next add the tomato puree, spices, salt and pepper. Cook for 3~4 minutes.
Add ½~1cup water and bring the mixture to a simmer. Cook for 2~3 minutes. Turn off the heat and keep ready.