Prepare the garlic, ginger, scallions, onion, and pork belly.
Place the pan on high heat, add oil, and stir-fry the garlic, ginger, scallions, and pork.
Once fragrant, add the black bean paste and stir-fry until the moisture is reduced and the paste is slightly darkened and is sticking to the pork.
Season with soy sauce and continue to stir-fry.
Once fragrant, add the onion, and toss to absorb flavor.
Season with oyster sauce, keep stirring all throughout.
Taste and adjust with sugar and MSG as needed.
Cook noodles according to package instructions, drain, then wash with cold water.
Plate the noodles, top with the sauce, and enjoy!