Your main objective is to clear the cake bomb. After that, this level will be a piece of...cake. The cake bomb will remove one layer of jellies (therefore, no need to worry about single jellies).
Thankfully, no part of the cake bomb is isolated from the board. Simply making matches or running a striped candy or two through it will be the most effective way to clear the level. A colour bomb + striped candy will also remove many slices of the cake. After clearing the cake, the jellies will reveal themselves underneath; namely the last ones you need to clear.
Use the rest of the moves that you are given to clear away the few jellies that survived the cake bomb knockout.