Cut the bitter melon in half lengthwise and remove the seeds and soft inner parts.
Chop into small pieces.
Place in water and let soak for about 10 minutes.
Drain and rinse the melon.
Chop the onion, garlic, pimento peppers, and tomato.
Heat oil in a frying pan over medium heat.
Add onion, garlic, and pimento peppers and cook until the onion is tender.
Add the bitter melon and stir to combine.
Cook until the melon softens and starts to lightly brown.
Add the chopped tomato and mix in.
Season with salt and black pepper to taste. Cook for another 1–2 minutes, then remove from heat.