ISO Korean dried noodles in TO
The jap chae dish featured in the NY Times on Monday requires sweet potato noodles ('dang myun"), which are dried and sold in a large plastic package. The noodles are translucent and greyish-beige in colour, and they are often sold in lengths of about 11 inches. You can find these at any Korean or Asian grocery store in the noodle aisle including Galleria at York Mills and PAT Oriental at Christie and Bloor. A picture of one package is attached.
The NYT recipe is pretty classic; japchae recipes rarely get too funky or, I guess, untraditional. In any case, the napa cabbage is not necessary but spinach, shiitake mushrooms, and carrots are imperative. I find that when making japchae, it's all about seasoning so don't be afraid to add more of the soy sauce-sugar-sesame oil mixture to it to taste.
I often like to buy extra amounts of spinach and some of the other vegetable ingredients in the recipe to use for other Korean dishes. For the spinach, I like to season before I toss them in with the noodles and make an extra amount of seasoned spinach to make bibimbap (the Korean rice dish with mixed seasoned vegetables and bulgogi marinated beef) later on. One recipe for Korean seasoned spinach can be found here:
And for the shiitake mushrooms, I've always seen dried not fresh shiitake mushrooms used. You should soak the mushrooms in boiled water then preserve the broth, which is really mellow and great for using in risotto dishes. Koreans also like to add other mushrooms to the dish, such as (rehydrated) cloud mushrooms.
If you consume meat products, the dish is often tossed with marinated beef (bulgogi) as well and/or thin strips of egg omelet.
You'll be able to find all these ingredients for japchae at the PAT Oriental Market at Bloor and Christie. Good luck!