Instructions

1. Trim the top off the onion: Cut enough off the onion that you cut through all the papery outer layers and expose the onion rings.
2. Trim off the root end (optional): I feel that cutting away the root end makes it a bit easier to cut very thin, very neat slices. Leave the root attached if you'd like a little more stability as you slice.
3. Slice the onion in half: Stand the onion on one of the cut sides and slice it in half.
4. Peel the papery onion skin from both halves.
5. Lay one half on the counter, like a dome. Turn the onion so that you'll be slicing along the lines of longitude, from top end to root end.
6. Beginning on one end, slice radially toward the center: Hold your knife at a slight angle and cut slightly inwards, toward the middle of the onion. The first few slices don't need to actually need to go all the way through to the very center of the; just work radially from the side to the center gradually increasing the angle of the cut as you work toward the center.
7. When you reach the middle of the onion, stop and tip it over: This makes it easier to slice the other half of the onion without holding your knife at an awkward angle. Now you can cut this part of the onion the same way you cut the first part.
8. Slice the rest of the onion as you did before. Be careful when you start to get to the middle so that your knife doesn't slip. Keep your fingers out of the way as best you can! (If you left the root end attached, cut it away once you're completely finished slicing the onion.)
9. Repeat with the other half of the onion.