Toss 12 ounces thinly sliced flank steak and ¾ teaspoon baking soda together in a medium bowl. Let sit at room temperature for 30 minutes. Meanwhile, make the sauce, cook the noodles, and make sure all the remaining ingredients are prepped and ready to cook.

Whisk 3 tablespoons soy sauce, 2 tablespoons oyster sauce, 1 teaspoon granulated sugar, and 1 teaspoon toasted sesame oil together in a small bowl.

Bring a large pot of water to a boil over medium-high heat. Add 8 ounces dried lo mein noodles and cook according to package directions, stirring occasionally, until tender. Drain the noodles. Rinse well with cold water. Let sit in the strainer to drain thoroughly.

Rinse the sliced steak well with cold water. Pat the steak dry with paper towels. Wipe out the bowl the steak was in (no need to wash). Return the steak to the bowl and toss it with 2 teaspoons cornstarch, 1 teaspoon kosher salt, and 1 teaspoon black pepper.

Heat a wok or large frying pan over high heat until it just starts to smoke. Add 2 tablespoons of the vegetable oil. Add half of the steak in an even layer and sear well-browned and just cooked through, around 1 minute per side. Using a slotted spoon or tongs, transfer to a bowl or plate. Add the remaining steak to the pan and repeat searing and transferring to the bowl.

Reduce the heat to medium high. Add the remaining 1 tablespoon vegetable oil to the pan. Add 2 minced garlic cloves, the thinly sliced whites of 2 medium scallions, and 1 medium minced shallot. Stir-fry until starting to brown, about 30 seconds. Add 1 peeled and matchstick-cut medium carrot, and 1 matchstick-cut medium red bell pepper. Stir-fry until the vegetables are crisp-tender, 1 ½ to 2 minutes.

Add the noodles and stir-fry until heated through, about 1 minute. Add the soy sauce mixture and stir-fry until everything is evenly coated in sauce, about 1 minute. Return the steak and any accumulated juices in the bowl to the pan. Add 6 ounces trimmed snow peas and stir-fry until heated through, about 1 minute. Garnish with the thinly sliced greens of 2 medium scallions.