In case you haven't heard, many chefs recommend cracking eggs on a FLAT surface. When you hit a raw egg on a sharper edge, you're more likely to get a small piece of shell in the egg (because the sharp edge pushes small shell pieces inside). Many people like how an edge helps to break eggs cleanly into two large sections, but that's a trade-off for producing more small fragments.
Something we've discovered is that a flat surface also works better for small, less-coordinated hands! Not only does the raw egg come out more slowly, but (most importantly) the egg is already OVER the surface where you want it to fall. Young kids have a hard time coordinating multiple connected movements (they often need to practice one at a time), so cracking an egg on an edge and then swiftly moving it to the interior of a bowl can be very challenging (and frustrating). Instead, we use a large plate so we can use the wide surface to both crack the egg and open it.
Steps for Cracking a Raw Egg
I usually dump each egg into a bowl (or plastic bag) after our Tiny Chef cracks them so he doesn't end up trying to crack a new egg on top of the old one (and so it's less likely new fragments will get into the already clean egg).