Scallops with Rhubarb Sauce

A couple of years ago, innovative restaurant chefs started using rhubarb in a similar way to sorrel, to sharpen buttery sauces for fish and meat dishes. The simplest version, first published in The Good Food Guide 1985, is from Franco Taruschio of the Walnut Tree Inn near Abergavenny (long cited by fans as the only source of good restaurant-foo