Peara' - Veronese Pepper Sauce for Boiled Meats

Take a pot, ideally terracotta, and melt equal volumes of unsalted butter and very fresh bone marrow.
Then add very finely ground bread crumbs, and stir well with a wooden spoon while they absorb the grease. Once they have stir in some broth, ideally made with meat, as opposed to poultry. Simmer over a very low flame for at least a couple of hours, stirring it every now then and adding more liquid if it starts to dry out. Then salt it and season it with a goodly grinding of black pepper -- not so much as to make it eye-watering, but enough to give it considerable zing.
The finished sauce should have the consistency of a thick mustard of the kind that has whole mustard seeds in it.

The bread crumbs should be toasted, and that the dish is quite old, as combining bread crumbs with fat is the precursor to working butter and flour together to make beurre manié.