Frying the paste until the oil splits

How to tell it is going right

• It is being fried, not simmered: the paste is in fat over live heat and moving, holding a steady sizzle throughout rather than bubbling as a wet mass.
• The colour has deepened and darkened from raw to cooked, and the volume has visibly reduced and tightened.
• The split, the signal the whole technique is named for, is unmistakable when it comes: clear fat separates out and pools at the edges and on the surface, and the paste pulls away from the pan floor in one mass.
• The smell has turned from sharp and raw to round and fragrant, with no raw bite left from any of the aromatics that went into it.
• Nothing has caught: no black specks through the paste, no bitterness, and a pan floor that is browned but not burnt.

Where it goes wrong It was taken off as soon as it smelled good, before the fat separated; the raw edge of the aromatics is still in it, and the finished dish tastes thin and sharp no matter how long it simmers afterwards.