The icing on the cake.
The icing on the cake.
The icing on the cake" refers to an extra benefit or enhancement that makes a good situation even better, much like how icing improves an already delicious cake. It is often used to describe something unexpectedly positive added to an event or achievement that was already deemed satisfactory.
Winning the game was great, but the trophy was the icing on the cake.
Winning was great, but receiving the trophy was an added bonus.
She finally got her promotion, which was the icing on the cake to her year.
Getting promoted was the highlight of her year.
After a day of fun activities, the unexpected free tickets to the concert were the icing on the cake.
The unexpected concert tickets were a delightful addition to an already fun day of activities.