Load up Story Mode on Kitchen. You'll spawn on the kitchen table, and you should be able to see a butter dish(?) just ahead of you. Remove the lid by gripping it and flinging it away, and start coating yourself in butter. This is accomplished by sliding around on the top of the butter until you think you've got the entirety of the side coated. Then, flip and do the same to the other side. You'll know once you're completely coated. From there, make your way over to the stove on the opposite side of the room.
You can do so by climbing onto the very top of the chair nearest to the counter and having it tip over to the counter for you to climb up, and then climb up the fridge and scale the side of the wall to get to the stove. Alternatively, you can fly from the table to the counter, and then from the counter to the stove, by destroyer the jar of jam on the table, grabbing a piece of glass (using
,
,
or
) and launching yourself around the room using basic flings (you fly farther when you're holding a small object).
Once you're at the stove, grip the second knob from the front on turn it to turn on the closest burner. Cook yourself to completion and end the level. If you didn't take any edibility damage along the way, I would recommend toasting each side to 142% (the maximum) so that your edibility drops to exactly 1% for the Walking Bread achievement if you don't already have it.
Here's a video guide for those who prefer it:
Following this path, you will unlock: