Bring plenty of water to a boil in the saucepan.

Quarter the onion and roughly chop it. Thinly slice the garlic.

Slice the mushrooms, seed the bell peppers, and cut them into strips.

Cook the rice, covered, for 10 minutes. Drain if needed and set aside uncovered.

Heat the oil in the wok or sauté pan. Sauté the onion and garlic over medium-high heat for 2 to 3 minutes.

Add the chicken strips and flour, then cook for 3 to 4 minutes, stirring.

Crumble the stock cube over the wok. Add the bell peppers and mushrooms, then cook for 5 to 7 minutes.

Add the kecap manis and water. Mix well and let the sauce reduce over medium-high heat for 3 minutes, or until nicely thickened.

Add the bean sprouts and cook for another 1 to 2 minutes.

Season with salt and pepper to taste.

Divide the rice between plates.

Spoon the saucy stir-fry over the top.