-
1
Place the trotters, neck bones, and back bones in a large stockpot. Cover with cold water and bring to a vigorous boil over high heat. Boil for 10 minutes: grey foam and blood proteins will rise aggressively to the surface. Drain entirely, discard the blanching water, and rinse each bone individually under cold running water until the water runs clear. The bones should show no grey residue. Return the cleaned bones to the pot.
-
2
Cover the rinsed bones with 4 litres of fresh cold water. Bring to a full rolling boil over the highest available heat. This is where the dish lives or dies: the boil must be sustained and violent — not a simmer, not a gentle bubble, but continuous turbulent agitation for the full extraction period of 8 to 12 hours. The constant motion and high heat deliberately emulsify the fat and dissolving collagen into the liquid. Do not reduce the heat. Top up with boiling water as needed to keep the bones submerged. The broth will begin beige and progressively whiten as emulsification proceeds.
-
3
After a minimum of 4 to 6 hours at a rolling boil, assess the broth for whiteness. A finished Hakata-style tonkotsu is white — not beige — and coats the back of a spoon with a thin film. Continue boiling toward 8 to 12 hours for maximum opacity and body. Taste: the broth should be intensely porky and thick on the palate from dissolved gelatin, but not bitter or grey in flavour — if it is, the blanching step was insufficient.
-
4
If making mayu: cook the separated, unpeeled garlic cloves in a dry pan over the lowest heat, turning occasionally, until the cloves are completely black throughout — not merely charred on the outside but black through the centre when cut. Blend the blackened cloves with 60 ml of neutral oil until smooth. The result is a paste that is bitter-sweet and intensely aromatic. Reserve 1 teaspoon per bowl for service.
-
5
Strain the finished broth through a fine sieve, pressing the bones lightly. Discard solids. Pre-heat four serving bowls with boiling water; the gelatin content of tonkotsu is high and the broth solidifies rapidly in a cold vessel. Pour the water out immediately before service. Place the tare (dissolved salt solution) in each pre-heated bowl — approximately 7–8 g salt equivalent per portion — then ladle the hot broth over it and stir to combine. If using milk enrichment, add 50 ml whole milk per litre of broth at this point; do not allow to boil again.
-
6
Cook the thin straight noodles to kata firmness — erring toward underdone, as they continue cooking in the bowl. Shake the cooked noodles thoroughly in the strainer to remove excess surface starch, then transfer immediately to the hot broth without delay. The noodles should be firm and carry resistance; excess surface starch would cloud the broth. Arrange chashu, halved marinated egg, and spring onion over the noodles. Add a teaspoon of mayu, if using, swirled at the surface.