Walkthrough
After finding and activating the Hidden Switch in Honey Hill, you will unlock the extra level of Extra Eclair. This level takes place in another forest of some type, this time during the nighttime. At the beginning of the level, there will be three separate places where you will need to break boxes and stumps to reveal the correct path to take. The correct path goes in this order: Top, Middle, and then Bottom.
After going through the second door of the level, head to the middle area of the grass and hover above with Kirby. By doing this, you will find another key, one that will help you unlock the locked door to the right. Make sure you have four characters when you do, as you will soon need all the help you can get. Once you pass through the door, simply keep proceeding and you will come across the next Rainbow Puzzle Piece.
Near The End of the Extra Eclair, you will have you next Mini Boss fight. This time, however, it is against two different Mini Bosses: Bonkers and Vividria. Like Mr. Frosty, these two aren't that difficult to defeat. All you must really do is keep attacking them while avoiding there attacks - that's all. After defeating Vividria, make sure to take her Artist Copy Ability. This will allow you to paint the portraits just up ahead, allowing you to find even more Puzzle Pieces.
Copy Abilities
Bonkers, Vividria