In a large skillet or wok, heat oil over high heat. Add onions and eggplant and stir fry for 8~10 minutes or until onions are lightly browned around the edges and eggplant is tender.
Add tomatoes, brown sugar, chile sauce, soy sauce and lime juice. Cook for 3~4 minutes.
Next add the bean sprouts, salt and pepper, cook for 2 more minutes.
Garnish with mint and serve with sticky rice or noodles.