Marrow bones with pine nut, garlic & Parmesan bone-marrow sauce

I have to say that this incredibly rich and intense ‘sauce’ is one of my all-time favourites. Onyou’ll see how I serve it with poached venison in a slightly different format, but in this instance it makes a great tapa, spread over toasted sourdough - especially if served with a glass of chilled fino sherry - a match made in heaven really. Any leftovers can be warmed up and spooned over grilled or roast beef. For the marrow bones, I simply asked my butcher