Then, cut the onion through the root to create two equal halves. Peel back any papery skin that is remaining on the onion, discard it, and lay the two halves on the cutting board, cut-side-down; this will give the onion stability as you cut.
Holding the blade of your knife parallel to the cutting board, carefully slice into the middle of one of the onion halves being careful not to cut all the way back to the root; you want the two pieces of onion to remain attached to each other. For larger onions you may need to slice it into thirds, again, being careful to keep all three pieces attached.
Next, with the tip of your knife pointed toward the onion's root, cut through the top of the onion at equal intervals. Like before, be careful that you do not cut all the way back to the root.
Then, with your fingertips tucked back to avoid injury, carefully slice through the onion half crosswise, producing a dice.
Continue cutting at even intervals for uniform pieces.
