It could depend on the cake that the talker is imaging Both are building a picture with a final action that "topped" everything else So it may depend if the talker has more experience with an iced cake, weddings , anniversaries and birthdays or cakes with cherries at a coffee shop or for dessert

Thanks, Lounne!

Hi Natalia, They both mean the same thing. Is "cherry on top" outdated? That's a difficult question to answer because it depends on the person and the context (spoken, written). Some people use idioms and others don't. If you want to use it, then use it!