Possible Clues:

• Gravy morsel
• Thanksgiving gravy ingredient
• Gravy ingredient
• Internal organ of a fowl
• Kind of gravy
• Gravy goody
• Chicken gizzard or liver
• 'In the plural, they're edible internal organs of a fowl (6)'
• Chicken's heart, e.g.
• Edible internal organ of a fowl