1. On a cutting board, remove the stem and root ends of the onion. 
   
   
2. Cut the onion in half through the stem and root, remove the outer layer of onion skin, and place the onion cut side down.
   
   
3. Working with one half at a time, place the onion cut side down and with one of its round edges facing your knife.
   
   
4. Angle your knife at 45 degrees from the cutting board and begin slicing into matchstick-size pieces.
   
   
5. Continue cutting in a radial manner, gradually changing the angle of the knife with each cut.
   
   
6. By the time you reach the middle of the onion, your knife should be at a 90-degree angle to the cutting board. When you’re most of the way through, and it begins to feel a little unstable, flip over the onion and continue slicing.