The goal when chopping an onion is to obtain evenly sized pieces that will cook at an even rate. Professional chefs often slice, dice, and chop at record speed, and this can make the task seem very intimidating to the home cook. But as you'll learn with practice, you can easily chop an onion down to size with methodical cutting techniques.
Use your knives properly for safe and efficient ingredient preparation.
HOLDING YOUR KNIFE: The first step in learning how to use your knives is to get the right grip. For the most control, choke up on the knife, with the thumb and index finger actually gripping the heel of the blade. Make sure you're working with a sharp knife. Learn more in our in-depth guide on how to sharpen kitchen knives.
USE THE "BEAR CLAW": Proper positioning can protect fingers. Using the “bear claw,” tuck fingertips in away from the knife to hold food in place and minimize danger by resting knuckles against the blade. During the upward motion of slicing, reposition your guiding hand for the next cut.
How to Chop an Onion
Many chefs lop off both the top and the root end before chopping an onion. However, for the average home cook, we find that leaving the root intact makes it easier to keep the layers together as you make each cut. The distance between the cuts made in steps 2 through 4 will determine the size of the final pieces. For chopped or diced onions, leave 1/4 to 1/2 inch between each cut. For minced or finely chopped onions, leave 1/8 to 1/4 inch between each cut. Learn more about understanding cutting terms.
STEP 1: Halve onion pole to pole—that is, cutting through top and root end. Peel onion and trim top. (It’s much easier to remove the skin once the onion has been cut.)
STEP 2: Lay peeled onion half flat side down on cutting board. With your hand on top of onion, make several horizontal cuts from 1 end to other but don’t cut through root end.
STEP 3: Make several vertical cuts. (Be sure to cut up to but not through the root end.)
STEP 4: Rotate onion half so root end is in back. Slice onion thin across previous cuts. Use your knuckle as guide for knife while holding onion with your fingertips. Pull your fingertips in towards your palm, extending knuckles outward when cutting for more control.
How to Understand Cutting Terms
"Minced" means 1/8-inch pieces or smaller. "Chopped fine" means 1/8- to 1/4-inch pieces.
"Chopped medium" means 1/4- to 1/2-inch pieces. "Chopped coarse" means 1/2- to 3/4-inch pieces.
How to Slice Onions Into Rings
STEP 1: Start by trimming 1/4 inch from one curved side to create flat surface for steady cutting.
STEP 2: Place onion cut side down on board, then slice into rings.