Cut the beef into pieces, and slice the onion and bell peppers into strips.

Add a little oil to the pan and stir-fry the beef until just cooked.

Add the onion and stir-fry together.

Add 1 tablespoon of oyster sauce.

Add 1 tablespoon of soy sauce.

Now add the pepper.

Then add the bell peppers.

Finally, add the cooked noodles.