olive oil or vegetable oil • small onion, sliced • garlic cloves, minced • medium tomato, diced • bitter melons, sliced (to prepare, cut in half lengthwise, remove seeds, slice into half moons) • Water or stock (if using stock, be mindful of salt) • soy sauce (to taste) • salted shrimp paste (bagoong) or fish sauce -- optional • egg, beaten