This is very close to the seasoning used at the famous Bookbinder's in Philadelphia.
1 1/2 tablespoons celery seed
1 1/2 tablespoons salt
2 teaspoons cayenne pepper
1/2 tablespoon dry English mustard (Colman's)
1/2 tablespoon whole thyme
1 tablespoon paprika
1 teaspoon freshly-ground black pepper
1/2 teaspoon dried ground ginger
2 whole bay leaves, crushed
Grind all ingredients in a food processor. Store in a covered container.