Mark developed his recipe for black garlic from an ancient Korean recipe, but beyond the fact that it involves slow- cooking at a warming-cupboard kind of temperature, he won't let on what else is involved! The bone marrow will need to be ordered from your butcher in advance; he may well expect you to buy the bones as well, in which case you will need to scoop the marrow out with the end of a teaspoon.
4 slices of sourdough
1 onion, finely chopped
120-150g bone marrow cut into rough 1cm pieces
60-70g fresh white breadcrumbs
6-8 cloves of black garlic, peeled and thinly sliced
A couple of handfuls of parsley, washed and finely chopped
Salt and freshly ground black pepper
A handful of flat leaf parsley leaves, washed and dried
2 shallots, thinly sliced
1tbsp rapeseed or olive oil
½tbsp cider vinegar
Heat the butter in a heavy-based saucepan and gently cook the onion for 2-3 minutes without colouring. Add the bone marrow, black garlic and parsley and cook on a medium heat for another 2-3 minutes, then stir in the breadcrumbs, season to taste and remove from the heat.
Toss the parsley and shallots in the oil and vinegar and season. To serve, toast the bread, spoon the bone marrow on top, then pop under the grill for another minute or so. Serve with the shallot mixture on the side.