Cut the potatoes into 7–8mm thick sticks and soak them in water for 5 minutes. Drain lightly. Slice the onion thinly. Halve the bitter melon lengthwise, remove the seeds and pith with a spoon, and cut into 5mm slices.

Cut the sausages diagonally into halves.

Place the potatoes in a microwave-safe container, cover loosely with plastic wrap, and microwave at 600W for 2 minutes. Drain any excess water.

Heat salad oil in a frying pan over medium heat. Add the onion, bitter melon, and sausages. Stir-fry until softened. Add the potatoes and cook until they develop a golden crust.