- 4 15cm centre-cut veal marrow bones, halved lengthways (see note)
- 185 ml veal demi-glace (see note) (¾ cup)
- 4 thick slices sourdough, toasted, halved crossways (8 pieces total)
- Finely chopped chives, chive batons and chervil, to serve
- 185 ml sherry vinegar (¾ cup)
- 185 ml white wine vinegar (¾ cup)
- 2 tbsp caster sugar
- 2 tbsp light brown sugar
- 8 golden shallots, finely chopped
- 250 ml buttermilk
- 150 ml thickened cream
- 4 gm agar-agar (see note)
- ¼ tsp xanthan gum (see note)
- 1Cover bones with cold water in a large container, cover and refrigerate for 2 days, changing water 2-3 times to leach blood from bone marrow.
- 2For sweet and sour shallots, bring vinegars, sugars and 1½ tsp salt to the boil in a saucepan, whisking to dissolve sugar. Stir in shallot, reduce to a simmer and cook, stirring occasionally, until reduced to a jammy consistency (20-25 minutes). Cool to room temperature, cover and refrigerate until required.
- 3For buttermilk purée, process buttermilk, cream and agar-agar in a high-speed blender for 30 seconds, transfer to a large saucepan, bring to the boil and boil for 1 minute to hydrate agar-agar. Pour into a wide shallow pan and refrigerate until set (1¾-2 hours). Break into smaller pieces, transfer to a blender and process on high speed until smooth. Sprinkle in xanthan gum and ½ tsp salt and blend to combine. Transfer to a squeeze bottle or piping bag and refrigerate until required.
- 4Preheat a grill to high. Drain marrow bones and pat dry with paper towels. Place cut-side up on a wire rack in a roasting pan, season to taste and grill on a low rack until heated through and the tip of a small knife inserted into marrow for 20 seconds feels hot (6-7 minutes), then grill closer to heat until top of marrow is golden brown (2 minutes).
- 5Combine demi-glace and ¼ cup sweet and sour shallots in a small saucepan and bring to the boil. Simmer until reduced by half (4-5 minutes). Brush a little on bone marrow, and scatter bone marrow with finely chopped chives.
- 6Spread about 2 tsp sweet and sour shallot on each piece of toast, pipe dots of buttermilk purée on top and scatter with chervil and chive batons and serve with bone marrow.
You’ll need to order marrow bones in advance from your butcher and ask for them to be cut through the middle. Demi-glace is available from some butchers. If it’s unavailable make your own by simmering 1 litre good beef stock with 1 tbsp red wine until reduced to 1 cup. Agar-agar and xanthan gum are available from select health-food shops and Asian supermarkets.
Drink Suggestion: Recaredo Turo d’en Mota Cava, Catalonia – not released until at least 10 years after the vintage, cava keeps a lively quality while developing flavours of roasted macadamia nut and baked Granny Smith apple, with acidity to cut through this rich dish. Drink suggestion by Fahara Zamrano