Caramelised onions appear in every tradition in your database — French soupe à l'oignon, Turkish pilav base, Persian rice dishes, Palestinian musakhan, Indian biryani. The technique is universal and universally under-executed: the process takes 45–60 minutes minimum at medium-low heat, not the 10 minutes most recipes claim. Ottolenghi's musakhan onions are the Levantine exemplar of the technique taken to its full depth.
Onions cooked at medium-low heat in generous oil or fat for 45–60 minutes until they have collapsed completely, turned a deep amber-brown, and become sweet, jammy, and intensely flavoured through Maillard reaction and caramelisation of their natural sugars.
Properly caramelised onions are one of the foundational flavour builders of world cooking — they add sweetness, depth, and umami simultaneously. In musakhan they are so abundant they are effectively a sauce in their own right. Their Maillard compounds interact with sumac's tartaric acid to produce a flavour combination that is the taste of Palestinian cooking.
- Start with more onions than seems necessary — they reduce to approximately one-fifth of their raw volume - Medium-low heat throughout — high heat browns the surface while the interior remains raw and harsh. Low, patient heat converts the onion's structure completely - Stir occasionally, not constantly — constant stirring prevents the Maillard reaction from occurring on the pan contact surface - Salt added early draws moisture, accelerating the softening stage - The pan fond that builds during cooking is flavour — deglaze with a small amount of water or stock if it threatens to burn Decisive moment: The colour check at 45 minutes — properly caramelised onions should be deep amber, significantly reduced, jammy in texture, and smell of deep sweetness with no raw onion note remaining. If they are still pale or translucent at this point, the heat was too low or insufficient time has passed.
OTTOLENGHI JERUSALEM — Technique Entries OT-01 through OT-25