Caramelized Onion, White Bean, and Tomato Soup

Deep flavor in this hearty main-course soup

Caramelized onions are smooth and mild, yet intensely flavored. And they make every other ingredient they touch taste much better.

They play a starring role in this Caramelized Onion, White Bean, and Tomato Soup. We like to ladle up big bowls of it for a main course, often served with a side of crusty bread. But you could serve smaller portions as a starter.

Even if onions make you cry, these will soothe your tears.

Recipe: Caramelized Onion, White Bean, and Tomato Soup

You probably know the iconic flavor of caramelized onions from French onion soup. But they work equally well when cooked with other ingredients.

The trick to caramelizing onions is time: They require long, slow cooking to develop their dark brown color and intense flavor. They can cook mostly on their own, but you do need to check on them frequently. So it’s best to make this soup on a day when you’ll be doing other things in the kitchen.

We like to use white beans in this soup, but you could substitute another variety if you prefer. And although we think tomatoes add terrific flavor and color, you can skip them if you want and just add more stock (we like to use chicken stock, but you could substitute beef or vegetable).

Prep time for this recipe is about 20 minutes. Caramelizing the onions takes at least 45 minutes (we usually allow an hour). Then the soup will need to simmer for another 30 to 45 minutes (this part can be done entirely unattended).

This recipe yields a bit over 2 quarts of soup. Leftovers keep for a few days if refrigerated in an airtight container. Or you can freeze them for a month or two.

Ingredients

• ~2 pounds onions (we like to use yellow onions, but any variety will work)
• 3 tablespoons butter
• 1 tablespoon olive oil
• 1 teaspoon kosher salt (see Notes)
• ~½ teaspoon sugar (optional, but helps promote browning)
• 2 15-ounce cans white beans
• 4 cups chicken stock (may substitute beef or vegetable stock, or water)
• 1 28-ounce can diced tomatoes
• 1 teaspoon dried thyme
• 1 to 2 sprigs fresh rosemary
• additional rosemary sprigs for garnish (optional)
  

Procedure 

1. Peel the onions. Cut them into halves or quarters through the poles (we like to quarter them, but suit yourself). Then slice the onions very thinly (see Notes). 
2. Place a heavy soup cooking pot or a large saucepan over medium stovetop heat (use a cooking pot that holds at least 4 quarts). Add the butter and olive oil. When the butter is melted, add the sliced onions. Cover the pot and cook for 10 minutes.
3. Add the salt and sugar, then stir to combine. Cover the pot again and cook (stirring the onions every 3 to 5 minutes) until the onions are well browned but not blackened. This process will take at least another 30 minutes, and perhaps as long as 45. Be careful not to burn the onions – if they appear to be scorching, lower the heat. 
4. Meanwhile, open the cans of beans and pour them into a strainer or colander placed in the kitchen sink. Rinse off the gunk the beans are stored in. 
5. When the onions are fully caramelized, add the chicken stock, tomatoes, beans, dried thyme, and rosemary sprig(s) to the cooking pot. Bring the mixture to a simmer and cook for at least 30 minutes (preferably 45).
6. Taste the soup and adjust the seasoning if necessary.
7. Ladle up! We like to garnish each bowl with a small sprig of fresh rosemary.
   
   

 Notes

• A mandoline makes slicing onions easier – but mandolines can be scary to use (the blades are very sharp, so wear protective gloves). They’re also a pain to clean. So we usually just slice onions by hand using a sharp knife (it really doesn’t take much longer).
• Two pounds of onions, when thinly sliced, will produce an impressively large heap. But they cook down to very little as you caramelize them. 
• It’s not strictly necessary to add sugar in Step 3. But it definitely helps the caramelization process.
• If the onions start to burn as you caramelize them, lowering the heat will help (but stirring them more often will help even more).
• This recipe makes a moderately thick soup. If you want a thinner consistency, add an additional 2 cups or so of stock.
• We like to use chicken stock in this soup, but beef stock works too. Or vegetable. You could also just use water, but the flavor won’t be as good.
• Feel free to vary ingredients in this recipe to suit your taste. You might want to add additional vegetables, for example. We think zucchini would work particularly well in this soup. 
• Want extra garnish? A sprinkling of grated Parmigiano-Reggiano cheese would work well.
• You could also chop a handful of parsley and stir it into the soup right before serving.
• We use kosher salt in cooking. It’s less salty by volume than regular table salt (the crystals are larger and more irregular, so they pack a measure less tightly). If you’re using table salt, start with about half the amount we suggest. But always season to your taste, not ours.
   

 

Use the Farce

“Yum,” said Mrs. Kitchen Riffs. “Layers of flavor in this soup.”

“It’s the onions,” I said. “Layers, they have.”

“Well, Yoda, you came up with an a-peeling recipe,” said Mrs K R. “Know onions, you do.”

High praise from Mrs K R. Tearing up, I am. Must be the onions.

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