Soak ½ cup of dried miyeok (seaweed) in cold water. After 30-40 minutes, the seaweed should have grown in size. Drain the seaweed through a sieve. Then use your hands and squeeze the water out of the seaweed. Then grab a pair of kitchen scissors and chop the seaweed into bite-sized pieces.
Use a knife and cut a piece of beef brisket (~150 grams) into small bite-sized pieces. Place the small beef pieces between a few paper towels and pat it down - this is to get rid of any excess blood or liquid (which makes for a cleaner broth). Set it aside.
Place 1 Tablespoon of Sesame Oil into a wok or pot. Turn on medium-heat. Once the oil is hot, add the beef pieces in. Then add in the seaweed. Add in the Kosher Salt (1 teaspoon!) and Soy Sauce (½ Tablespoon). Stir-fry it around for 3-5 minutes - this process brings out a deep flavor from the seaweed. (Note: If the pieces start to stick to the pot and you see the seaweed pieces "melt on" to the sides - you've been stir-frying for too long - immediately move onto next step)
Then add 2.5 cups of water. Once it comes to boil, let it boil away for a few minutes.
Afterwards, place in remaining 2.5 additional cups of water.
Then add in Fish Sauce (½ teaspoon!) & Soy Sauce (½ Tablespoon). Then some minced garlic (1 Tablespoon).
Then place a lid on - and let it gently simmer for 30 minutes on LOW heat!
After 30 minutes, turn off the heat. Let it sit for 5-10 minutes - so the flavors can come back together. Then sample soup - it should be spot on! But If it tastes slightly bland, add-in a splash more of soy sauce OR a sprinkle of kosher salt. Conversly, if it tastes slightly too salty, add-in a splash of water. Then let it cook for a few minutes more if you made adjustments.
Plate and serve with a bowl of rice.