The two-layered icing limits playing space, but there is not much of it.
The target scores are relatively low. It should not take much effort to reach them.
Plus, there are only five colors, making it easy to create special candies.
Strategy
Remove the icing as fast as possible to open the board space.
Then, keep making matches to reach the target score within the time limit.
Extra time candies will fall when a match triggers three cascades, and then every four cascades afterwards. Use this wisely to extend the level's duration, as it is a crucial aspect of all timed levels.
Trivia
This is the third level to introduce two new things: Two-layered Icings and Timed levels.
As of this level, all five of the original level types in Candy Crush Saga have appeared.