Possible Clues:

• Freezing during picnic in garden
• Spotting, not missing, white coat
• Pastry-tube filling
• Decoration's not completely exotic in gastronomy
• Cake coat
• Top cake layer
• Sugar coating as cake decoration
• ... I croon to the audience, putting a coat on
• 'Happy Birthday' makeup, perhaps
• Setter's heard to inform on cake decoration