Roasted bone marrow (os à moelle) is the rôtisseur's simplest and most decadent preparation — cross-cut or split beef marrow bones roasted until the marrow is soft, trembling, and translucent, served in the bone with coarse salt, toast, and parsley salad. Marrow is almost pure fat (approximately 80%), but it is a specific fat — rich in oleic acid (the same monounsaturated fat that makes olive oil healthy), with a clean, buttery, almost umami flavour that is distinct from any other animal fat. The preparation: have the butcher cut femur bones into 7-8cm sections (canoe-cut lengthwise for presentation, or cross-cut rounds). Soak in cold salted water for 12-24 hours, changing the water 2-3 times — this draws out blood from the marrow, producing a clean white colour. Drain and pat dry. Stand the bones upright on a parchment-lined sheet pan (this prevents the marrow from melting out of the bottom). Roast at 220°C for 15-20 minutes — the marrow should be soft and beginning to pull away from the bone slightly (it jiggles when tapped), but not melted into a liquid. If the marrow is overcooked, it liquefies completely and runs out of the bone — there is nothing to spread on toast. Serve immediately in the bone, with a long, narrow marrow spoon for extraction. The accompaniment: thickly sliced sourdough toast, fleur de sel, cracked black pepper, and a salad of flat-leaf parsley, shallot, and capers dressed in lemon juice and olive oil. The parsley salad's green freshness against the marrow's unctuous richness is a contrast of extraordinary satisfaction. Scoop the marrow onto hot toast, sprinkle with salt, top with a pinch of parsley salad.
Soak 12-24 hours in salted water — this draws out blood for a clean, white, presentable marrow Roast upright (bones standing) — this prevents the melted marrow from running out 15-20 minutes at 220°C — the marrow should be soft and trembling, not liquefied Serve in the bone with a marrow spoon — extraction at the table is part of the ritual Parsley salad is essential — the acid and freshness cut through the extreme richness
A tiny sprinkle of smoked Maldon salt on the marrow instead of regular fleur de sel adds a subtle smokiness that is extraordinary For the Fergus Henderson presentation (St. John, London, adopted from French bistro tradition): serve the bones on a napkin-lined plate with a generous pile of parsley salad and a stack of thick-cut toast — the simplicity IS the sophistication Save the roasted bones — they still contain flavour and can be added to your stockpot for an incredibly rich, gelatinous bone broth
Not soaking — the marrow has veins of blood that turn grey and look unappetising when roasted Roasting too long — the marrow melts entirely and runs out of the bone, leaving an empty cylinder Laying bones on their side — the melting marrow pools and drains out one end Serving without the parsley salad — the richness of pure marrow without acid and freshness is overwhelming Serving on cold plates — the marrow solidifies rapidly on contact with cold ceramic
Escoffier, Le Guide Culinaire; Larousse Gastronomique