Meat Sauce for Black Truffle Cannelloni with Bone Marrow and Rabbit’s Brains

INSTRUCTIONS

1. 1
   Reduce the meat juices to form a fairly thick, flavorsome sauce. Bind with cornstarch if necessary. Set aside. Brown the butter in a pan. When hazelnut color, deglaze with the sherry vinegar. Add the meat juices and season with salt. Keep warm.