The 6 Best Onions for Spaghetti Sauce 

Despite the onion being such a commonly used ingredient in many cuisines, we often don’t think twice when adding onion to the pan while cooking up our dinner. However, they are a great and important base flavor that can really bring the rest of the ingredients into balance.

For example, in traditional French cooking, onions are always included in the ‘mirepoix’ that’s sauteed at the beginning of most sauces, stews, soups, and is even celebrated with its own signature dishes such as French onion soup.

The problem is that, nowadays, most recipes will not specify what kind of onion is needed or what is suitable for that particular recipe. This may have you thinking that all onions are the same and that it doesn’t really matter which one you use.

However, there are distinct flavors and qualities to varieties of onions that you may not be aware of. Choosing the right onion could really enhance the dish you are making and the quality of your cooking.

A basic tomato spaghetti sauce is a great example to use to show how choosing the right onion can improve the taste of a dish.

A basic spaghetti sauce has very few ingredients so selecting the right onion could really help create a much more complex flavor rather than just the taste of tomatoes. So, I hear you ask, what is the best onion for a spaghetti sauce? Well, let’s find out…

To show you the importance of the onion in your recipes, let’s explore what makes a great spaghetti sauce, how the right onion can enhance your spaghetti sauce, and why you should give more thought to the onions you put into your meals.

What kind of onion do you use for spaghetti sauce? When considering the flavors of a tomato-based spaghetti sauce, tomatoes tend to be a little sweet but also quite sharp and acidic. The best onion to use would be a yellow onion or sweet onion.

By slowly sauteing and caramelizing the onion, bringing out its natural sweetness, you will balance out that acidic flavor of the tomatoes and bring a more mellow rounded flavor to the sauce.

Best Onion for Spaghetti Sauce

When choosing the right onion that will suit the recipe you are making, it’s a great advantage to understand the different textures and tastes each onion could bring to your dish as well as want each type is commonly used for.

1. Yellow Onion

Yellow Onion

This is the most commonly known onion; white/yellow flesh, thin layers, and brown dry skin. Not often eaten raw as it has a very astringent spicy taste.

Because of its high sugar content, it is super sweet when cooked and offers a great caramelized flavor and texture to dishes. Works best in roasted meat dishes or as part of a flavor base for sauces, soups, and stews.

2. Sweet Onion

It has thicker layers than a yellow onion but has a similar high sugar content though not quite as pungent due to the low level of sodium.

These qualities make it great for dishes that require a bit more of a crunchy texture such as onion rings, roast vegetable dishes, and creamy gratin traybakes. It is also traditionally used in French onion soup to bring sweetness and texture to the thin broth.

3. White Onion

White Onion

A more unusual onion with its distinct white skin but not always easy to find in supermarkets. This variety is a very crunchy and crispy onion due to its high water content. Most commonly used in Mexican cooking and eaten raw in salsas. Works well in light cooking such as a stir fry.

4. Red Onion

Red Onion

This is the best onion for when the dish or recipe calls for raw onion. It has a much more mild flavor than yellow and sweet onions with only a slightly bitter after taste.

It is also a great onion to use if you want to add some vibrant color to the dish. Works great in dips like guacamole, tossed into salads, or as a topping for burgers and sandwiches.

5. Shallots


Shallots are more closely related to garlic rather than onions but very often are used in the same way as onions.

They have a similar flavor to red onions but tend to be used in more refined cooking. Works best in vinaigrettes, dressings, egg dishes, or as a delicate garnish.

6. Spring Onion

Spring Onion

These are baby yellow onions that are harvested before the onions have fully grown. This results in a much more mild flavor and means you can also eat the green tops.

Spring onions are often used in Asian-style dishes by being added to marinades, salad dressing, stir-fries, or used as a raw garnish. Like the red onion, it is also a great option when wanting to add vibrant color to the dish.

How do you cut onions for spaghetti sauce?

There are many ways to cut an onion and the one you choose for your spaghetti sauce will depend on what kind of texture is needed for the sauce and how prominent you want the texture of the onion to be in the dish.

For a chunky spaghetti sauce, having a slightly caramelized thinly sliced onion will add another texture to the dish but not be too thick that it’s hard to eat with thin spaghetti noodles.

Here is the best way to finely slice an onion:

  • Cut the onion half, lengthways from top to bottom.
  • Peel and discard the skin.
  • Chop off the top of each half but leave the ends still attached.
  • This makes it easier to slice.
  • Take one half of the onion and place it flat side down on the chopping board. With a sharp knife parallel to the onion, thinly slice the onion to create half-circle shaped onion pieces.
  • The slices should be about 1 or 2 millimeters thick. Keep going until you reach the root of the onion. Discard the root once finished. – Repeat this step with the other half of the onion.

What onion is used in Italian food?

In traditional Italian cooking, yellow onions are used for cooking (ie, in sauces, soups, and stews) and red onions are eaten raw and used for salads or garnishes.

Yellow onions are added to the base for pasta or pizza sauces, rice dishes and sauces made to accompany meat or fish. While red onions would be used for bruschetta, antipasti,  or as a pizza topping.

A traditional Italian onion variety is the Cippolini onion which literally translates as ‘little onion’. They are about the size of a golf ball but are a flat disc shape.

These onions have a sweet delicate flavor and are often just roasted whole or sauteed in butter and herbs and served as a great side dish.

For a more authentic Italian spaghetti sauce, it is best to use a yellow onion.

How do you make an easy spaghetti sauce from scratch?

The key to a good spaghetti sauce is patience and time. You want to allow the sauce to cook and simmer away for a longer time than you would think; you want to let it cook for at least 30 minutes.

This allows the tomatoes to lose their water and get richer in flavor but also allows the onions to get sweet and soft.

There are a variety of recipes and methods for making a great spaghetti tomato sauce. Our quick and easy version is kept chunky and full of texture using fresh plum tomatoes, garlic, fresh basil, and of course a yellow onion to add some sweetness and more complexity to the predominant flavor of the tomato.

Easy Spaghetti Sauce Recipe

Spaghetti Sauce

  • 1 handful of fresh basil leaves
  • 1 medium yellow onion
  • 2 cloves of garlic
  • 1 kg ripe plum tomatoes, (or 2 x 400g tins of quality chopped tomatoes)
  • olive oil 1 tablespoon
  • red wine or balsamic vinegar

Peel and finely slice the onion and garlic. If using fresh tomatoes, cut them in half, and roughly chop.

Put a saucepan on medium heat. Add 1 tablespoon of olive oil and the sliced onion.

Cook for about 8 minutes, or until the onion has gone soft and lightly golden.

Stir in the garlic for a few minutes, before adding in the fresh or tinned tomatoes and the vinegar.

Season with a pinch of salt and pepper, then allow to simmer on medium heat and cook for around 15 minutes. Stir occasionally.

Stir in the chopped basil leaves, reduce the heat to low, and leave it to cook for another 10 minutes.

Serve with freshly cooked spaghetti, topping it with extra basil leaves and traditionally a sprinkle of grated Parmesan cheese.

Hopefully, this article has helped you improve your homemade spaghetti sauce and has given you some insight into the importance of onions in the recipes you make.

With the understanding of what different onions can bring to a dish and how they enhance the other ingredients, you can start being more creative in the kitchen and experiment with finding the best onion for your other favorite recipes.

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