Before the onion’s cut there’s a pause, as a pianist's hands hover over keys, before Chopin on a rainy afternoon, languid, pensive, the stillness before the skin’s broken and notes are fulfilled. Extravagant talk for the ordinary onion, yet I'll claim it, if only for the sheer number I've chopped. I timed myself the other day, and it takes me 7 minutes to peel and dice 12 onions. 
Sharpen knife, chop off both ends, run knife down the skin making a shallow slit from end to end. Take off peel in one curved movement. Slice in half from head to root and lay down both on flat sides. Hold half firmly with fingers curled back out of knife’s range, and with cutting arm begin rhythmic thin slicing from rounded side to rounded side, flip small pieces left over at end and cut. Turn sliced half as one, and chop in other direction head to tail, go on to next half… infinitum.
The ways, my students chop onions in classes are painful; hand pick off the peel for 15 minutes, cut it into thick rounds with the peel on, try to core out the root end….It is a mysterious sphere, in a wrapping, and will make you cry, literally as you try to master it. Painful to watch, but I’ve realized, the perfect way to assess where students are as cooks, and what they’ll need in practice to move on.
Orion, my 14 year old apprentice is learning to chop onions as we make soup. He brings a sharp chef’s knife with him, but he’s free, at least outwardly of ego and attitude about his beginner’s skills. He just wants to learn to cook and learn it well. I appreciate that, nothing’s more tedious than dealing with someone’s onion ego when they don’t have a clue about how to get from here to there, and are petrified of being judged as imperfect!
I start him out with a bag of onions each week. I demonstrate and then he copies. He asks for clarity, I show him, he practices. I leave him completely alone for 5-6 onions, and then I stand across from him and silently chop at my skill and speed as he works concentrated at his. I remind him that it’s just a practice. He reminds me that it’s not as easy as it looks, that indeed it does take skill. He gets teary, those onions!
It’s springtime, the right time to show him how the onion's still alive, how it’s striving to make a make a flower, and go to seed. I show him the developing green bud inside of every bulb. I want him to connect the onion to earth, seeds, bulbs and season. It’s not been manufactured for us in the bag. Onions stored overwinter, like every plant wants to get on with life as the light increases. 
Lilies of the field, yet we take their raw bite and with attention transform them; court their inner sweetness with sharp knives and fire.