How To Dice An Onion

How to Dice an OnionPin

Onions are one of the most magical ingredients you can add to a dish. This tear-inducing, sharp flavored vegetable features in most savory recipes.

They excel in creating a base flavor in different sauces and are often the staple ingredient in worldwide dishes such as curry, soups, and spaghetti bolognese.

Nutritious, cheap, and available at all times of the year, onions complement and even complete many recipes.

However, many of us still struggle to prepare them properly without experiencing sore, watery eyes. Just the mere memory of this puts a whole host of people off cutting these strong veggies.

While there are different kinds of onions from the sweet variety to red onions, dicing them is the same across the board.

Dicing (cutting food into small cubes) is important in many recipes. Without dicing, onions may not cook evenly and large pieces of onion may not go down so well with people.

If you’re struggling to dice an onion correctly, we are here to help! You’ll be pleased to know that there are a few methods of cutting onions.

And these will not see that knife slipping all the time and putting your digits in jeopardy. The first dicing method we will show you below will guarantee the onion pieces will be the same size with every cut.

So, all you need is a sharp knife, a cutting board, and an onion. If you’re ready, let’s dice an onion together.

Dicing with a knife

Firstly, we are going to dice an onion with a knife. But before you start, make sure the knife is sharpened or at least sharp enough to cut through an onion with ease.


1. Cut ½ an inch (1.3 cm) from the top of your onion – The top (stem) is the pointed area of the bulb. Set the onion on a cutting board and measure down from the top by around ½-inch. Cut straight through with the flat edge of the knife on top of the onion.

2. Cut the onion in half from top to bottom – Place the cut side of the onion face down on your cutting board. Press the knife into the middle of the root on the top. Cut through the onion to reveal two halves of the same size.  

3. Peel the outer skin of the onion back – Pull the outer skin of both halves of the onion off and discard it. Pick the edge of the next peel under this layer and pull it back toward the root without removing it entirely. This remaining peel can act as a handle to hold onto as you cut the onion.

4. Cut straight lines toward the root – Hold the peel of the onion near its root. On one side, place your knife’s tip ½-inch away from the root. Now, make vertical straight cuts up to the flat edge you cut away earlier. Do this across the whole onion with each cut the same distance as the other. 

5. Make 2 to 3 sideways cuts from the onion’s flat side – Lightly press down on the onion and place the knife’s blade parallel to the cutting board. Cut into the onion’s flat side around ½-inch up from your cutting board.

Your knife should be angled down to protect your fingers. Stp cutting as you reach the root. After the first cut, make further slices that are equal distance apart until you reach the top of your onion. 

6. Slice lengthwise for dicing – Place your onion so its root is the same side as your non-dominant hand. With your fingertips on top of the onion, the knife blade should touch your knuckles. Cut through the onion on its flat side.

After every slice, move your fingers back to guide the knife. Continue cutting until you reach the root. Again, all cuts should be the same distance apart. 

And that’s it! Your onion is now ready to add to a platoon of recipes.

Let’s take a look at another method, using a food processor.

Dicing with a food processor

1. Cut the onion in half – Remove the stem and root so you are left with two flat edges. Set the onion on one side of the flat sides in an upright position. Cut through its middle to be left with 2 pieces around the same size. 

2. Take away the outer peel – Tear off the outer peel with your fingers. You may have to pick at it with your fingernails to separate fully. Pull this peel off completely so you’re left with a smooth surface.

3. Place the two pieces of onion in your food processor – Put the onion halves on opposite sides of your processor’s container. Ensure the onions are not sitting directly on top of the blades as this may hinder the dicing process.

Securely place the lid back on the processor. Just be extra careful when putting your onions in the food processor as the blades are very sharp and can easily cut you. 

3. Press the “Pulse” setting to dice your onions – After you press the button, just watch the processor cut your onions. Press and hold the Pulse button for around 2 to 3 seconds at a time. Then let go and see if the pieces are small enough for you.

Continue this until you’re happy with the sizes of the pieces. Don’t pulse your onions too long as they will become liquified and may not work in your recipe.

What to look for in onions

When choosing onions for your recipe, always pick firm ones without any soft spots or sprouts. Black or brown spots are signs that the onion is going moldy.

Onions with green sprouts should be avoided as these are not fresh and will spoil quite quickly. The onion should feel solid without any discoloration.

Once you have your onions, they should stay healthy and edible for up to 3 months in your pantry or refrigerator.

In Summary

So, that’s how to dice an onion easily. Once you get the hang of this, you will be able to dice an onion in seconds and add it to a range of delicious recipes.