Related Clues:

• "Happy birthday" writers, perhaps
• Cake decorators
• Bread and cake makers
• Those with a lot of dough
• Johnston, Mooney and O'Brien are capable of producing bloomers
• Champagne buckets, e.g
• Cupcake finishers
• People with decorating tips?
• 'Happy Birthday' artists, perhaps
• 'Happy Birthday' writers, often
• Bakers, on occasion
• Dessert makers
• Bread-makers
• Cupcake-topping workers
• Johnston, Mooney and O'Brien are the ones responsible for the bloomers