In a large bowl, add beef short ribs; pour enough cold water to cover ribs. Cover with plastic wrap and let it sit for at least 1 hour to over night in a refrigerator. Drain, rinse under running water and get rid of small bone bits. Drain completely and set aside.
Combine soy sauce and next 4 ingredients in a bowl and stir until honey dissolved.
Heat a Dutch oven or a braising pot over high heat; add oil and place one layer of prepared ribs. Be careful not to crowed pot, cook 3 to 4 batches. Sear 2 to 3 minutes each side and set aside. Repeat until all ribs are seared. Tab excess oil with paper towels as you go. After last batch, turn off heat; you will see lots of oil left in pot. Remove oil completely by tapping with paper towels.
Place seared ribs back into pot along with sauce we made earlier and sliced red onion. Turn on stove to medium heat; stir ribs, sauce and onion all together to mix well and scrape bottom of pot with an wooden spoon.
Cover, simmer for 25 minutes and then reduce heat to low simmer for additional 20 minutes. Stir occasionally so they will cook evenly.
Transfer to a serving dish and sprinkle sesame seeds, drizzle some sesame oil to taste and garnish with Korean red pepper thread. Serve warm, enjoy!