Trim the fat from the flank steak and cut it into 2-inch chunks.

Place the beef chunks into a pot, cover with water, and bring to a boil to parboil.

Once boiling and foam appears, remove the parboiled beef from the pot.

Discard the water, thoroughly wash the pot, and rinse the parboiled beef in cold water.

Return the cleaned beef to the pot, add 4 cups of water, cover, and cook over medium heat for 50 minutes.

Cut two large serrano peppers into chunks and soak them in cold water to reduce spiciness.

Slice a large onion and prepare 12 peeled garlic cloves.

After 50 minutes, add 1/2 cup of soy sauce and 1/2 cup of water to the pot.

Add the prepared onion, garlic cloves, and drained serrano peppers to the pot.

Stir everything together, cover the pot, and continue to cook over medium heat for another 20 minutes.

After 20 minutes, turn off the heat and let the Jangjorim cool down.

Remove the cooled beef chunks and tear them into shreds along the grain.

Place the shredded beef in an airtight container, then add the cooked vegetables and pour the braising liquid over everything. Store in the refrigerator.