Preheat oven to 350 degrees F.

In a small container thoroughly mix thyme, mustard, celery seed & garlic powder. [NOTE: I usually just rub the thyme between my thumb & index finger to crush some of the leaves.].

Rinse the roast & pat it dry with paper towels.

Rub herb mixture over the roast [OR roll the roast in it].

Place fat side up on a rack in a shallow roasting pan.

Roast, uncovered about 3 1/4 hours.

About 30 minutes before end of roasting time, insert meat thermometer with tip in center of largest muscle of roast.

Roast should be ready to remove from oven when internal temperature reaches 165 degrees F.

Cover with tent of foil, then let stand 10-15 minutes before carving, during which time internal temperature SHOULD reach 170 degrees F.