Possible Clues:

• Sweet that's Italian or American -- I ruin it when served up
• Whipped up, it is a rum dessert
• Atrium is changed for a desert
• Mixture of it with a rum is sweet
• Sweet thing from Mauritius mixed with upper-class once
• Is it a rum cocktail that's sweet?
• Embracing Welsh day of celebration, American and Italian served up dessert
• Redesigned atrium covering is sweet
• A truism I debunked, sweet!
• Cocoa-dusted dessert