Bone Marrow Custard with Sourdough Soldiers and Parsley Oil
Umami velvet on toast — the bit most folk bin ends up in a glass.
Bone marrow's been London posh grub for years, but it's the custard spin — whipped with eggs and cream, gentle heat — that makes it sing. Saw a butcher in Smithfield pull a femur from a grass-fed Hereford one winter morning, cracked it open like it owed him money. The marrow was bright, almost fluorescent. Worth every penny and every second of respect.
How to Cook It
- 01
Roast the marrow bones
Heat oven to 200°C. Lay split bones marrow-side up on a tray, season with fleur de sel and white pepper. Roast for 12–15 minutes until the marrow is loose but not melting (you want it to scoop clean). Let cool for 2 minutes, then scoop into a bowl. You'll have about 150g soft, yielding treasure.
~20 min - 02
Make the custard base
Sieve the roasted marrow into a bowl — discard any grit or bone dust. Whisk egg yolks and cream together in a separate bowl until pale and ribbon-like, about 2 minutes. Season with a small pinch of fleur de sel. Fold the marrow into the eggs gently, three turns of the spoon — don't overwork it.
~5 min - 03
Cook the custard
Set a bain-marie (saucepan of simmering water) on the stove. Place custard bowl over it — the water shouldn't touch the base. Stir constantly with a rubber spatula, scraping corners, for 8–10 minutes. You're looking for the texture of softly whipped cream: thick enough to coat the back of a spoon, but not scrambled. Remove from heat the moment it's set; carryover heat keeps cooking.
~12 min - 04
Make the parsley oil
Blanch parsley in boiling salted water for 30 seconds, then straight into ice water. Squeeze dry in a clean tea towel. Blitz with olive oil in a tall jug using a hand blender for 90 seconds until vivid green. Pour through fine-mesh sieve lined with muslin, let it drip (don't push). You'll have luminous, bright green oil.
~8 min - 05
Toast the soldiers
Slice sourdough into 1cm-thick planks, then cut each into fingers. Lay on a tray, brush lightly with olive oil, season. Toast in the oven (still at 200°C if it's on; if not, use a dry pan over medium heat) for 3–4 minutes per side until golden and crisp. They should sound hollow when tapped.
~8 min - 06
Plate and serve
Spoon warm custard into small glasses or ramekins — it should wobble slightly, not set firm. Drizzle parsley oil over the top in a thin thread. Place two sourdough soldiers on the rim or alongside. Finish with a single grain of fleur de sel and a whisper of white pepper. Eat warm, using the soldiers to dunk and drag through the custard.
~3 min
“Serve in a small coupe glass or shallow ramekin so the custard's sheen catches the light. The parsley oil should sit on top like a green silk scarf, not mixed in. Toast the soldiers warm and place them where they can dunk — on the rim, propped against the glass. Fleur de sel scattered across the top, not stirred in. This is a messy, tactile eat: encourage folk to use their hands.”
First spoonful: umami wallop, like beef stock concentrate made silken. The egg and cream carry the marrow without drowning it. Dunk the soldier through and you get toasted grain, slight bitter edge, then back to custard's buttery swathe. Parsley oil cuts through it like a bell — mineral, peppery, clean. Finish is savoury-sweet, almost brothy, sticks with you for hours.
Replace the marrow custard with a cashew and truffle cream: soak 150g raw cashews in hot water for 20 minutes, drain, blitz with 80ml oat milk, 1 tbsp white miso paste, and 1 tsp black truffle oil until silken. Warm gently in a bain-marie (cashew mixture breaks if overheated; keep below 60°C). Serve in the same glasses, topped with parsley oil and sourdough soldiers. The miso gives umami depth; truffle mimics marrow's savoury earthiness. Cashew cream should be thick but not dense — add a splash more oat milk if it sets too firm.
Minerality echoes the parsley oil; acidity slices through the custard's richness without apology.
Caramel sweetness and low ABV let the marrow breathe; nutty backbone matches the toast.
Umami mirrors umami — comforting, complete, the amuse becomes a small ritual.
- ·Don't overheat the custard — scrambled marrow is sad marrow. Bain-marie at a gentle simmer, stir constantly, pull it off the heat while it still trembles.
- ·Source your bones from a butcher who grinds them fresh — supermarket precut marrow bones are often oxidised brown inside. Bright pink or cream means it's good.
- ·Parsley oil separates if it sits; make it 30 minutes before service and keep it in a warm spot. If it splits, whisk in a teaspoon of water and it'll come back together.
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