Bibim-guksu.

Chef Ryu called this recipe 설마 — "no way." As in, no way gochujang alone can make a bibim-guksu this good. Yoo Jae-suk ate it on TV, converted on the spot, and the internet followed. Enough people cooked it that Ryu came back with a fully-tuned version.

The chant is 4·4·4·6 — sugar, vinegar, sesame oil at 4 each, soy at 6. That's the backbone. The rest is small numbers. And one non-obvious move: a spoon of the cucumber-and-onion pickling brine goes back into the sauce. Do not skip.

Ingredients

The quick pickle (오이·양파 절임)

• 1 cucumber (오이), mandolined into thin ribbons
• ½ onion (양파), mandolined thin
• 2 tbsp sugar
• 4 tbsp vinegar
• 3 pinches salt

The 4·4·4·6 yangnyeom (per big batch)

• 4 tbsp sugar
• 4 tbsp vinegar
• 4 tbsp sesame oil
• 6 tbsp jin-ganjang (Korean dark soy)

The supporting cast

• 2 tbsp gochugaru
• 2 tbsp toasted sesame seeds
• ½ tbsp gochujang
• ½ tbsp minced garlic
• 1 tbsp ketchup — the secret rounding-off ingredient
• 1 tbsp of the pickle brine — the umami hook (add last)

The noodles

• 2 bundles somyeon (Korean thin wheat noodles)

Method

1. Pickle the veg. Mandoline cucumber and onion into a bowl. Add 2 tbsp sugar, 4 tbsp vinegar, 3 pinches salt. Massage with your hands 30 seconds. Fridge for 15 minutes — no less. The cucumber should turn slightly translucent and the onion should collapse.
2. Build the yangnyeom. In a separate bowl, combine 4 sugar · 4 vinegar · 4 sesame oil · 6 soy. Whisk until sugar dissolves. Add gochugaru, sesame seeds, gochujang, garlic, and ketchup. Whisk again.
3. Add the brine. Spoon 1 tbsp of the pickling liquid from the cucumber bowl into the yangnyeom. Stir. Taste — it should be sweet-tangy-savory with a low chili hum. Adjust sugar or vinegar by ½-spoon if needed.
4. Boil the noodles. Bring a big pot of water to a rolling boil. Add somyeon. Cook 3 minutes (or per package). Do not oversalt the water — the sauce carries all the salt.
5. Shock and drain. Rinse under cold water, then plunge into ice water, rubbing gently. Drain very well — wet noodles dilute the sauce.
6. Dress. Toss noodles with 4–5 spoons of yangnyeom per portion (Ryu warns: 9 spoons for a big serving, 5 for smaller — add gradually and taste, because once it's over-salted you can't come back).
7. Plate. Mound noodles into a bowl. Top with a generous handful of the pickled cucumber and onion — this is not a garnish, it's half the dish. Finish with more sesame seeds.

Tip · the ketchup thing

Ryu insists ketchup goes in. Not for tomato flavor — for the acidity, the light sweetness, and the natural glutamates that round the gochujang. One spoon, no more. Try it once before you argue.

Tip · the pickle brine is the umami hook

Halfway through building the sauce, Ryu adds a spoon of the cucumber-and-onion pickling liquid — the salty-sweet-vinegary drain from the veg. He says this is what he settled on after many rounds of tuning. Skip it and the sauce feels flat. Add it and everything locks in.

Tip · 4·4·4·6 scales

The core yangnyeom ratio is 4 sugar · 4 vinegar · 4 sesame oil · 6 soy. Double it for company, halve it for one — the pattern holds. Everything else (chili, sesame, gochujang, garlic, ketchup, brine) stays roughly the same and adjusts to taste.

Tip · eat with samgyeopsal

On the show, they served this after grilled pork belly (삼겹살). The cold spicy-tangy noodles reset the palate between bites of fatty pork. This is the traditional Korean pairing and it's why the dish exists.