Japchae (Quick Korean Noodle Stir-Fry)

ounces dangmyeon (sweet potato starch noodles)*

divided

half a medium white onion, thinly sliced

shiitake mushrooms, thinly sliced

red bell pepper, cored and thinly sliced

large carrot, peeled and thinly sliced

garlic cloves, minced

fresh baby spinach

toppings: toasted sesame seeds, thinly-sliced green onions

maple syrup

toasted sesame oil

sirloin or flank steak, thinly-sliced against the grain into bite-sized pieces

soy sauce

Kosher salt and freshly-cracked black pepper