Slice garlic thinly. Cut onion into wedges, halving each crosswise to create large triangular pieces. Cut bell pepper into 1.5 cm strips, then into triangles.

Place beef in a small bowl and toss with one-third of stir-fry sauce.

Mix well and let marinate for a couple of minutes. No need for salt at this stage; sauce provides enough salinity.

Bring a pot of water to a boil. Season generously with salt.

Put noodles into boiling water. Cook for 7 minutes, stirring vigorously during first couple of minutes to prevent clumping.

Drain, rinse under plenty of running cold water to stop cooking process, and set aside until step 5.

Put cornstarch in a wide bowl.

Shaking off excess marinade, place meat in a single layer into cornstarch. Toss well to dress beef evenly on all sides.

It's gonna happen fast—have your mise en place ready: keep meat, rest of stir-fry sauce, chopped vegetables, slotted spoon or spatula and a paper-towel-lined bowl within arm's reach.

Turn on range hood.

Heat two tablespoons vegetable oil over medium-high heat until shimmering.

Shake off excess cornstarch and carefully lay beef in a single layer into hot oil. Sear for 30 seconds, then flip carefully and brown the other side for another 30 seconds.

Transfer meat with a slotted spoon to lined bowl to drain excess oil.

Keep skillet on heat.

Put onion and bell pepper slices into hot oil. Stir-fry for one minute, tossing pan constantly.

Add garlic and sweat for another minute, keeping it moving to prevent burning.

Return meat to pan and warm through for one minute. Fold in noodles and remaining stir-fry sauce.

Toss gently but thoroughly to coat, heating for a final 30 seconds.

Serve in a deep bowl. Garnish generously with sesame seeds.