Higher level poffins are made if you stir in the correct speed. Stir too fast and they'll overflow. Stir too slow and they'll burn.
When the poffin's color starts being different, stir a little bit more faster. But not too fast or too slow, too.
When a few colored dots appear on the poffin, stir more faster with the right speed.
(Here's a secret technique: When the poffin gets smaller, Stir as fast as you can! When the poffin gets too large, Stir really slow.)
This way, The poffin will have a high level.