How do you cook a 4 pound gammon joint?

If frozen then a 4 lb. beef roast will cook faster. Put the oven up to 400 (lid on roaster) for 20 - 30 minutes and sear, then put the temperature down to 350 and cook 15 minutes per pound. If the 4...

obviously 4

a good hour.

About 1 hour. I have had an 8lb buddaball ham in the past and cooked it for only 2 hours at 325-350 degrees.

Cook a turkey until the juices run clear. Insert a squewer into the thickest part of the turkey, and press down. When the juices are clear, you're turkey is done.