Chopping an onion is a fundamental cooking skill that serves as the building block for countless recipes. From adding depth to soups and stews to enhancing the flavor of sautés and salads, onions play a vital role in creating delicious and aromatic dishes. Let’s learn the quickest and easiest methods to cut an onion into the three most popular shapes: petals, slices, and cubes.

Preparation

Before you begin chopping an onion, it’s essential to ensure that you have all the necessary tools and equipment ready. This preparation will help you work efficiently and minimize the risk of accidents. Here’s what you need to do before starting to chop:

Selecting a Suitable Onion:

Choose an onion that is firm and free from any signs of mold or decay.
Ensure that the size of the onion is appropriate for the recipe you are preparing.
Keep in mind that different onion varieties have varying flavors and strengths, so choose one that complements your dish.

Gathering Necessary Tools and Equipment:

Sharp Chef’s Knife: A well-maintained, sharp chef’s knife is crucial for clean and precise cuts. An ideal knife should have a blade length of around 7-8 inches (18-20 cm).
Cutting Board: Use a stable cutting board with a non-slip, and flat surface to ensure your safety while chopping.
Bowl for Chopped Onion: Have a bowl or container ready to collect the chopped onion pieces. If you’re cutting an onion for salads, you can pour cold water into the bowl to soak the chopped onion, which will help release some of the fumes.
Optional: Onion Goggles or Chilled Onion: If you’re sensitive to onion fumes, consider wearing onion goggles or chilling the onion in the refrigerator for about 15 minutes before chopping to reduce the release of irritants.

By having these tools and equipment in place, you are ready to cut your onion.

How to Cut an Onion

Step 1. Removing the Onion’s Outer Skin

This step is applied regardless your desired shape of onion, from petals to slices or cubes.

Place the onion on the cutting board with the end facing down.
Use your fingers to peel away the papery outer skin, revealing the fresh onion layers underneath. Keep the root end intact to hold all the layers of the onion together while cutting.

Step 2: Cut the onion

1. Shape 1: How to Cut Onion Petals

Creating onion petals is a visually appealing and versatile way to incorporate onions into your dishes. This technique involves separating the layers of the onion to form petal-like segments. Follow these steps to master the art of crafting onion petals:

Keep the onion steady on the cutting board with the flat side down.
Make vertical cuts from the top towards the root end, stopping just before you reach the root. Ensure these cuts are evenly spaced, and their depth will determine the size of the petals.

Cut off the root ends. Now, all the layers are released.
Gently separate the layers of the onion with your fingers.

Benefits and Uses of Onion Petals:

Onion petals can enhance the visual appeal and flavor of various dishes, including salads, sandwiches, wraps, or stews like Vietnamese Beef Ragu. Their unique shape and texture add a touch of elegance to your culinary creations.

2. Shape 2 – How to Cut Onion Slices (Vertically)

Slicing onions thinly is a technique that enables you to incorporate delicate onion flavors into a variety of dishes. Whether you’re aiming for thin or thick slices for a quick sauté or a salad, follow these steps to consistently achieve evenly sliced onions:

Trim off the root end.
Place the onion on the cutting board and cut it vertically from the top towards the root end into 4 equal parts.
Lay one onion quarter on the cutting board with one cut side down.
Start slicing from the remaining cut side.
After 2-3 slices, flip the cut side and continue to cut 2-3 more slices. Keep flipping to ensure the slices are uniform in shape and length.

Onion slices are matched well with salads, beef or chicken pho, pickles, etc.

3. Shape 3 – How to Cut an Onion into Cubes

Keep the onion steady on the cutting board with the flat side down.
Make vertical cuts from the top towards the root end, stopping just before you reach the root. Ensure these cuts are evenly spaced.

Dice the onion horizontally to create small cubes. If it’s challenging for you to cut the entire onion, you can divide it into two halves and dice them one by one.
Cut it slowly and be careful to avoid accidents.

Diced onions are a kitchen staple used in countless recipes, including soups, sauces, stews, salads, and more. Their small, even size allows them to blend seamlessly into dishes, providing flavor and texture without overwhelming the other ingredients.

Safety Tips When Chopping an Onion

While chopping onions can be a rewarding experience, it’s important to prioritize safety to avoid accidents and injuries in the kitchen. Here are some safety tips to keep in mind:

Holding the Onion Securely:

Hold the onion with your non-dominant hand, keeping your fingers curled in a claw-like grip. This minimizes the risk of accidentally cutting your fingers.

Keeping Fingers Away from the Knife’s Blade:

Always maintain a safe distance between your fingers and the knife blade. Use the knuckles of your guiding hand to guide the knife while keeping your fingers tucked away.

Maintaining Proper Knife Skills:

Use proper knife techniques, such as the rocking or slicing motion, to maintain control over the knife’s movement.
Ensure the knife’s edge remains in contact with the cutting board to prevent the blade from slipping.

Using a Stable Cutting Board:

Place a damp paper towel or a nonslip mat under your cutting board to prevent it from sliding while you’re chopping.

Keeping Your Knife Sharp:

A sharp knife is safer than a dull one because it requires less force to cut through ingredients and reduces the risk of slips. Furthermore, slicing an onion ruptures its cell walls, releasing various enzymes that synthesize syn-Propanethial S-oxide, an irritating gas. Using a sharper knife minimizes cell damage, resulting in fewer released enzymes and, hence, a less painful experience when cutting onions.

Remember that safety should always be a priority in the kitchen. By following these safety tips and remaining mindful while chopping onions, you will create a safer and more enjoyable cooking experience for yourself.

How to Cut an Onion

Active Time: 10 minutes

Total Time: 10 minutes

Difficulty: Easy

Let's learn the quickest and easiest methods to cut an onion into 3 most popular shapes: petals, slices and cubes.

Materials

1-2 white/yellow/purple ornions

Tools

A sharp knife
A cutting board

Instructions

Step 1. Removing the Onion's Outer Skin

This step is applied regardless your desired shape of onion, from petals to slices or cubes.

Place the onion on the cutting board, root end facing down.
Use your fingers to peel away the papery outer skin, revealing the fresh onion layers underneath. Keep the root end to hold all the layers of an onion while cutting in the next steps.

1. Shape 1: Cut Onion Petals

Keep the onion steady on the cutting board with the flat.
Make vertical cuts from the top towards the root end, stopping just before you reach the root. These cuts should be evenly spaced, and their depth will determine the size of the petals.
Cut the root ends. Now all the layers are released.
Gently separate the layers of the onion with your fingers.

2. Shape 2 - How to Cut Onion Slices (Vertically)

Trim off the root end
Place the onion on the cutting board and cut it from the top towards the root end into 4 equal parts (vertical cut)
Lay one onion quarter on the cutting board, one cut side down.
Start slicing from the rest cut side.
After 2-3 slices, flip the cut side and continue to cut 2-3 slices more. Keep flipping so the slices uniform in shape and length.

3. Shape 3 - How to Cut an Onion into Cubes

Keep the onion steady on the cutting board with the flat.
Make vertical cuts from the top towards the root end, stopping just before you reach the root. These cuts should be evenly spaced.

Dice the onion horizontally to create small cubes. If it's difficult for you to cut the whole onion, you can divide it into 2 halves and dice them one by one.
Cut it slowly and be careful to avoid accidents.