How do you crack open eggs with one hand, like the chefs on TV? Obviously it takes a lot of practice, but how do they do it without getting pieces of shell in the food?
very carefully.
sorry, but that’s about it.
cracking your eggs against any surface (a knife, a cutting board, a bowl or pan edge, etc.) may produce stray shell fragments if done wrong (and by wrong, i mean “not exactly positively right”, and even then, doing it “the absolutely right way” may still lead to fragments. so to do it right, without leaving fragments, takes practice, and luck. the more you do it, the better at it you will get. but you won’t get it perfect.
still, the character of the shell, which differs slightly from egg to egg, will play a role. even t.v chefs will from time to time have bits of shell fall into their recipes (though you might have to look for blooper reels to actually see it.)
a quick strike & turn-to-break-open is your best bet, though it is never a bad thing to have learned some just-in-case eggshell-bit-removal-from-the-mixing=bowl=techniques.
besides, if you really care about cooking, it’s what you end up with, not how you got there, that is really important.
Alton Brown says that one should never break an egg on anything other than a flat surface, because it may lead to bits of shell being pushed up inside the egg.
Whatever. If anyone sees bits of shell after they crack an egg, they remove them, right?
If you really want to be able to crack an egg and drop it into the bowl with one hand, you’ll need to crack the shell on an edge (some say this is a no no) and splay your fingers in a way that parts the halves of the shell.
Do yourself a favor, and forgo the theatrics. Crack the egg sensibly, and make sure there are no shell fragments in it, that’s it.
Unless you need to compete in a “quick cooking” competition, the 2.5 seconds saved by cracking an egg with one hand do not matter.
Hold the egg in your dominant hand. Depending upon how big your hands are, you might hold it with your fingers only, though with my smallish hands, I actually have it rested against my palm as well. Thumb on one side of the egg, four fingers on the other. The index finger sits just below the peak of the egg, the pinky just above the base of the egg, and the other two placed so that there’s a wee bit more space between them then between each and the index or pinky, as the case may be. With me so far?
Crack the egg against an edge. Flat surface p’shaw. You don’t hit so hard that bits go flying into the egg, but you do hit firmly enough to get a definite break in both the shell and the inner membrane. Move your hand over the bowl or pan you want to break the egg into.
Then, pull towards the elbow with the index and middle finger. You’re essentially bending at the knuckle where the fingers join the hand. Your fingers will curl slightly, as they need to so that you continue to have a firm grip on the eggshell.
The egg should open enough so that the innards drop into the recepticle. And there you have an egg broken with one hand.
It does take practice. Don’t drop the innards from very high (duh) or the yolk will break. It’s not necessarily practical unless you’re cooking in a high-volume breakfast restaurant (where I learned to do it oh so many years ago). But it does look cool.
My aside: that I make my new friends fancy omelettes in the morning impresses them. Doing it with one hand says, “this man knows how to cook in the kitchen, too!”
Bugger the flat surface technique. Sorry Alton. My problem with that method is that it makes a larger, roughly circular crack pattern in the egg that may or may not break the membrane layer behind the shell. When that happens you have to awkwardly take a knife and puncture it a bit so you can finish extracting the contents from the shell. If you crack it just right on an edge, you’ll make a relatively clean, narrow crack that will almost always split the membrane in the process that usually doesn’t produce many small fragments, and unless you hit it too hard won’t push the ones it does up into the white.
The one-handed method really doesn’t get you anything but style points. 
The one-handed technique (well described by Standup Karmic) is also useful for separating eggs. You crack the egg with one hand, drop it gently into the other hand, and let the whites drip between your slightly splayed fingers. Then throw the yolk into a separate bowl.
Ditto what Standup Karmic says. The tricky part is not the one-handed part, it’s getting a clean break in the first step, which you do with one hand anyway. One the egg is properly cracked opening it with one hand is just a matter of practice. My approach is slightly different, holding the half nearest me with the middle, ring, and pinky fingers, and using the index finger and thumb to push open the half farthest from me. Care is taken not to thrust the thumb inside the egg.
I always break the egg against the edge of a metal bowl. I can crack two eggs at once, one in each hand, although I don’t do this if it’s important to keep the yolk intact because I usually break it this way.l
Also, if you really want style points:
If you’re cracking them by the dozen, you can with a little dexterity nest the emptied eggshell halves together with the cracking hand, then transfer them to other hand. This way you can keep cracking them and transferring them and when you’re done you’ll have a nice neat stack of eggshells, instead of a drippy pile to clean up.
Before I went back to college, I was a Sambo’s restaurant manager for a while. One of the things we did in the mornings was crack many dozens of eggs into a mixer (the large commercial mixer) bowl, add some cream and blend everything together with the wire whip attachment for the cooks to use when making scrambled eggs.
Instead of cracking eggs the usual two-handed way, I figured this was a great way to practice both cracking eggs and the one-handed method. I was right; it didn’t tak too many hundred eggs before I was a master at it.
That was over 27 years ago, and I can still do it one-handed without even thinking about it.
So, if you know someone at a restaurant that uses large quantities of scrambled eggs, you might consider “volunteering” to do this a few mornings at your local Denny’s or whatever if you want to get really, really, good at it.
I taught myself to do it and independently lit on the flat surface cracking method. I find in makes an place that easier to get your fingers into without scattering shell fragments. I can do it with an egg cracked on an edge, but the other method just seems to work more consistently.