Okay, so a butter rosette seems like a pretty old-fashioned way to decorate a plate, but this is still a pretty cool trick to have in your arsenal.
As you can see from the video below from The Mind of a Chef, it's a tricky technique to get right, requiring a steady hand and just the right level of knife control.
Luckily, chef Jacques Pépin is on hand to provide guidance. He has some pretty serious knife skills honed over a near seven decade career– watch him demonstrate seven different knife techniques, including how to make a tomato flower and a lemon pig.
There's also some great archive footage of Pépin demostrating his famous omelette making skills to enjoy too.