Place the beef into the freezer to let it firm up a little (see note).

Wash and drain 4 oz spinach.

Set aside 4 oz of dangmyeon (sweet potato starch noodles)

Cut 3 green onions crosswise into 2-inch-long pieces and place in a small bowl.

Thinly slice 1 medium yellow onion (about 1 cup when sliced) and place it in a small bowl.

Thinly slice 5 white mushrooms and place them in a small bowl.

Peel 1 medium carrot and cut into matchsticks (about 3/4 cup when julienned) and place in a small bowl.

Cut 1/2 red bell pepper into thin strips and place them in a small bowl.

Peel 1 clove of garlic and mince it into a small bowl.

Add 1 tbs of soy sauce.

Add 1 tbs of sugar.

Add 1/2 tsp of ground black pepper.

Add 2 tsp of sesame oil.

Stir to combine.

Set aside 1 tbs of toasted sesame seeds.

Cut 2 large shiitake mushrooms into thin strips and place them into a small bowl.

Cut 4 oz of lean beef into 1/4 inch wide and 2 1/2-inch-long strips and place into the bowl with the mushrooms.

Peel 1 clove of garlic and mince it into the bowl with the beef and mushrooms.

Add 1 tsp sugar to the beef and mushrooms.

Add 1/4 tsp ground black pepper to the beef and mushrooms.

Add 2 tsp soy sauce to the beef and mushrooms.

Add 1 tsp of sesame oil to the beef and mushrooms.

Mix the beef and mushroom mixture by hand.

Cover and refrigerate.

Add a pinch of salt and beat with a fork.

Add 1 tsp of vegetable oil to a heated nonstick pan. Swirl the oil around so it covers the pan and then wipe off the excess heated oil with a kitchen towel so only a thin layer remains on the pan.

Turn off the heat and pour the egg yolk mixture into the pan.

Tilt the pan around so the mixture spreads thinly. Let it cook using the remaining heat in the pan for about 1 minute. Flip it over and let it sit on the pan for 1 more minute.

Let cool.

Roll the egg and slice crosswise into 1/16th strips.

Bring a large pot of water to a boil.

Add the spinach and blanch for 30 seconds to 1 minute.

Remove the spinach with a slotted spoon or strainer and rinse under cold water to stop the cooking. Leave the boiling water on the stove.

Squeeze the spinach to remove any excess water.

Cut the spinach a few times and place it into a large mixing bowl.

Add 1 teaspoon of soy sauce to the spinach.

Add 1 teaspoon of sesame oil to the spinach.

Mix the spinach by hand.

Place the noodles into the boiling water.

Cover and cook for 1 minute.

Stir the noodles to prevent sticking.

Cover and keep cooking for another 7 minutes until the noodles are soft and chewy.

Strain the noodles under cold water.

Cut the noodles a few times with kitchen scissors and place into the bowl next to the spinach.

Add 2 tsp of sesame oil.

Add 1 tsp of soy sauce.

Add 1 tsp of sugar.

Mix well by hand.

Heat up a wok or skillet over medium high heat.

Add 2 teaspoons vegetable oil.

Add the onions and a pinch of salt.

Stir-fry about 2 minutes until the onion looks a little translucent.

Transfer to the noodle bowl.

Reheat the wok and add 2 tsp of vegetable oil.

Add the white mushrooms and a pinch of salt.

Stir-fry for 2 minutes until softened and a little juicy.

Transfer to the noodle bowl.

Reheat the wok and add 2 tsp of vegetable oil.

Add the carrot and stir-fry for 20 seconds.

Add the red bell pepper strips and stir-fry another 20 seconds.

Transfer to the noodle bowl.

Reheat the wok and add 2 tsp of vegetable oil.

Add the beef and mushroom mixture and stir fry for a few minutes until the beef is no longer pink and the mushrooms are softened and shiny.

Transfer to the noodle bowl.

Add the garlic/soy sauce/sesame oil mixture to the mixing bowl full of ingredients.

Mix all together by hand.

Add 1 tbs sesame seeds.

Mix and transfer it to a large plate to serve.