Possible Clues:

• Is it hardly edible?
• Small bun (said to look solid!)
• Managed OK with cracker -- cut another bakery item
• Tough type from the bakery introduces 6 down to Trim, Cork and Kildare
• Rough-looking hard bun
• A hard-baked sweetmeat
• Baked tooth-breaker?
• Is it cooked for a diamond wedding?