The Absolute Best Onion Variety For French Onion Soup

Not all onions are created equal

If you find yourself confused by the variety of onion types available at the grocery store—white, yellow, red, or sweet—you’re not alone. Here’s a quick guide to help you understand their differences and best uses. Generally speaking, white onions are milder and less pungent than yellow onions. Yellow onions, often referred to as brown onions, are the most commonly used variety. They have a stronger flavor with a bit of a kick, but when cooked, they soften into a delightful sweetness, making them ideal for dishes like French onion soup. Additionally, yellow onions are more robust and have a higher starch content, which helps them hold up during long cooking times.

The sweet onion variety, which includes Vidalia and others, is known for its mild flavor and lack of sharpness compared to white or yellow onions, as the name implies. These, along with white onions, are excellent choices for salads and sandwiches. On the other hand, red onions are typically the sharpest and most flavorful. While many people agree that yellow onions strike the perfect balance between sweetness and strength for soups, don’t hesitate to experiment with different types. You might even consider mixing various onions for a colorful and flavorful medley.

Caramelizing yellow onions is the key for a great soup

When it comes to a dish as onion-centric as French onion soup, both quality and quantity are crucial. So, grab those goggles or be ready for some tears, because you'll be slicing a significant number of onions. For a typical recipe, you'll need to finely slice at least three to four onions, depending on the size of your batch. The first and most vital step in creating that rich, signature broth is to caramelize the onions to perfection. The ideal degree of caramelization is often a topic of endless debate. Achieving a beautifully golden-brown color—dark, but not burnt—is essential for infusing your broth with the robust and sweet (never bitter) flavor that defines French onion soup.

If you cook the onions for too long, the soup can take on an unpleasant burnt taste that no amount of seasoning can disguise. Conversely, if you undercook them, you won't achieve the deep caramelization that this dish requires. This process demands time and focus, so you won't want to stray too far from the stove. However, when you allow ordinary onions to gradually sweeten and darken, the time invested in the kitchen pays off with a wonderfully cozy, warming, and savory soup.

Static Media is the owner and operator of Chowhound and Tasting Table.