Depend on the platform of different magic mixer behaviour, the strategy varies:
On web version, always remember to remove at least one layer of icings closest to the spawner, so that it will busy repairing those icings instead of far ones. Then you can safely dig a hole at far side.
On mobile version, it is suggested to reduce layers of all icings at the same time, since the spawner does not renew them until totally removed. When the ingredients are ready, quickly remove the remaining sachets and let them slip through.
In either case, save your moves as there are only 14.