Step-by-step instructions to show you how to cut onion petals.
Peel the onion first so you don't have to deal with pesky skin while you're cutting it. Save the skins and any scraps and freeze them to make stock later on. I keep a gallon bag in my freezer all the time for saving up veggie scraps.
Cut off the non-hairy end of the onion. Slicing off the end makes a flat surface so it isn't rolling around while you're trying to cut it.
Place the onion with the cut side against the cutting board and the hairy end on top. Cut off all four sides around the hairy end. You'll essentially have a core in the middle, which you won't be using.
Slice the four cut pieces into two or more segments to make them petal-sized. The pieces should be sized as evenly as possible so that they will all take about the same amount of time to cook.
Pull apart the onion layers. Now you have onion petals!