Definition of carbuncle for English Language Learners. : 1  a large painful swelling under the skin. : 2  a jewel (such as a garnet) that is cut into a rounded shape.
For a 12-14 lb (5.5-6.5 kg) turkey: Cook for 40 minutes then reduce the temperature to gas mark 3, 325 F (170 C) and cook for a further 3-31/2 hours. Then give it a final 30 minutes (uncovered) at gas mark 6, 400 F (200 C).
For a 15-20 lb (6.75-9 kg) turkey: Cook for 45 minutes then reduce the temperature to gas mark 3, 325 F (170 C) and cook for a further 4-5 hours. Then give it a final 30 minutes (uncovered) at gas mark 6, 400 F (200 C).