The 500-Year-Old Tuscan Onion Soup Recipe I Can’t Stop Making

There’s something so comforting about making traditional Italian recipes. Growing up in a big Italian family, I feel connected to these rustic dishes and the legacy of cozy meals made with love. Italian cooking has a way of turning the simplest ingredients into deeply flavorful dishes, and this soup is no exception. 

You probably know and love French onion soup (as you should), but you may be less familiar with the original onion soup—and you may be missing out! Carabaccia, a Tuscan onion soup that dates back to the 1500s, is lighter, sweeter, and just as comforting.

Instead of deeply caramelizing onions, it’s made by slowly cooking red onions until they’re tender and sweet. A touch of cinnamon adds unexpected warmth, and a splash of red wine vinegar brings the sweet-and-sour tang Italians call agrodolce.

Making carabaccia takes patience, but it’s less intensive than caramelizing onions for French onion soup. The slow, steady cooking of the onions is meditative, and the payoff is well worth it, resulting in a soup that’s subtly sweet, a little tangy, and impossible to stop eating. I know from experience.

Notes on the Ingredients

• Red onions: Sweeter than other onion varieties, they are the key to this dish. Don’t swap in yellow or white onions.
• Red wine vinegar: It balances the sweetness of the onions. Substitute white wine vinegar for a lighter, sharper flavor.
• Vegetable broth: Traditional versions sometimes use water, but the broth adds savory depth. Make sure you use high-quality or homemade broth.
• Cinnamon: This surprising ingredient is traditional and truly makes the soup. A pinch is all you need to bring out the sweetness of the onions.
• Herbs: These are optional and not traditional, but fresh sage leaves and bay leaves add an earthy, savory contrast.
• Salt: Season generously, especially if you are using low-sodium broth. The salt helps the simple flavors shine.

Tips for Softening Onions, Not Caramelizing

1. Cook with a lid on for the first 10 minutes. This allows the onions to steam and prevents any initial caramelization.
2. Keep the heat on low. Resist the temptation to crank up the heat and instead allow the onions to soften with time.
3. Stir regularly. This prevents the onions from browning through contact with the pan.

Serving Suggestions

Traditionally, Carabaccia includes ground almonds for protein and to add substance to the broth. The texture is unusual, so many modern versions omit it. To add protein while keeping the soup vegetarian, you can stir in cannellini or butter beans with the broth.

Carabaccia is often ladled over Italian bread, which is sometimes topped with grated parmesan cheese. A poached egg is another tasty addition. For a heartier meal, you can sauté Italian sausage before the onions and add it back when the soup is finished.

I recommend serving this soup in wide, shallow bowls. Don’t expect big bowls of brothy soup here—it’s really all about the onions, with just enough broth that you can eat it with a spoon.