Heat oil in a shallow or deep frying pan. Add onions and cook gently for 1 to 2 minutes. Add tomatoes, garlic, thyme and hot pepper; continue to cook gently for another minute.
Add bitter melon and stir, mixing with sautéed aromatics. Cook uncovered on medium to low heat until cooked, turning intermittently.
To determine when it’s done cooking, take a piece and bite into it, it should be soft. At the same time taste for seasoning (salt) if you’d put enough to taste at the onset, you should not need to add more, but taste just in case.