Step 1

Using a very sharp chef's knife, cut the onion in half cut in half vertically alongside the root.

Step 2

Peel off the outer layers and discard. Leave the root end intact to make it easier.

Step 3

To slice: Lay one onion half flat on your cutting board. Point the knife towards the root of the onion, and allow your fingers to guide the slicing. Slice vertically evenly as close to the root as you can. Cut off the root and discard.

Step 4

To dice: Lay one onion half flat on your cutting board. Point the knife towards the root of the onion, and allow your fingers to guide the slicing. Slice vertically evenly as close to the root as you can. Next, start dicing the onion by making horizontal cuts perpendicular to the one you just made. Cut off the root and discard.