Step 1

Cook noodles according to package directions. Drain and rinse under cold water. Set aside.

Step 2

Meanwhile, heat 1 tablespoon oil in a large flat-bottomed wok or cast-iron skillet over high heat. Add bok choy whites and cook, stirring, for 1 minute. Add bok choy greens and cook until wilted, about 1 minute more. Transfer all the bok choy to a medium bowl.

Step 3

Add the remaining 1 tablespoon oil, scallion whites, ginger and chili-bean sauce (or chile-garlic sauce) to the pan. Add pork and cook, crumbling with a wooden spoon, until no longer pink, 3 to 5 minutes. Add broth, tamari (or soy sauce) and sugar. Mix cornstarch and water in a small bowl and add to the pan. Bring to a boil and cook, stirring, until slightly thickened, about 1 minute. Stir in the reserved noodles and bok choy; cook, stirring, until heated through, about 1 minute. Serve topped with scallion greens and crushed red pepper, if desired.