Remove pot from oven and let stand 30 min. Discard spice bag. Transfer meat to bowl with cover. Place pot over med. high heat and bring sauce to boil. Cook, uncovered, until reduced by 1/4. Let cool; then pour into another container with tight lid. Refrigerate meat and sauce until well chilled. Cut away any congealed fat from sauce. Pour sauce into wide heavy-bottom saucepan. Heat until bubbling. Sprinkle with salt. Cut meat against grain into 1/4" slices. Immerse in sauce and heat through. Arrange meat on warmed serving platter in a neat pattern. Spoon with some of gravy; serve remainder in gravy boat. Garnish platter with watercress. Frances Prince's New Jewish Cuisine