It can take an inordinate amount of time to dice an onion or two if you’re not familiar with how to do it. I’m going to save you tons of time by detailing the quickest and most efficient way to do so. Once you master this, it will take you under a minute to dice a whole onion.
The first few steps to chopping or dicing an onion are identical. The first thing is to… well, get an onion. Remove the papery thin skin, exposing a lighter layer that is moist and clean. Next, slice off the hard knob and sprouting ends of the onion, the top and bottom. Then, cut the onion in half through those same two points.
Slicing the onion in two will help stabilize the onion as you are chopping or dicing it. Placing the onion flat-side down on your cutting board, make a series of cuts parallel to where you sliced off the two ends of the onion. DO NOT SLICE ALL THE WAY THROUGH! Leave about one centimeter attached at one end. From the bottom, your onion should now look like this, with a thin line attaching the fanned onion slices at the top:
The primary difference between a “chop” and a “dice” is in how far apart you make the slices. Usually, a dice is smaller and much more precise than a chop. After you’ve sliced the onion almost all the way through one way, make another series of slices perpendicular to the previous lines, all the way through this time. Think of it as a checkerboard pattern. You adjust the size of the checkerboard squares to result in a fine dice, medium dice, or a chop.
Your last step is to clean up the thin end you left connected previously, cutting it down to roughly the same size as the other pieces. You go through the same process with the other half of the onion, and before you know it, you’ve got a whole diced onion in under 60 seconds!
This procedure can be done with any type of onion, as well as shallots. Even if you’re using a sharp knife, the layers can shift easily, which is why having the stabilized onion halves and connected end for the first slices is so useful. It may take you a few attempts to get this process of dicing onions down, but if you cook regularly you will get a lot of practice.