From Dip To Soup, 3 Recipes For Cooking Onions — A Classic Kitchen Staple

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Onion Tart. (Jesse Costa/WBUR)
Onion Tart. (Jesse Costa/WBUR)

Here & Now resident chef Kathy Gunst has three onion dishes for host Robin Young to share, including her takes on the classic onion dip and soup. These recipes and tips come from Kathy's cookbook "Soup Swap," published by Chronicle Books.

Onions are the flavor base of so many cuisines around the world. They can be sharp and strong when raw, and sweet and silky when cooked long and slow.

11 Types Of Onions To Know

There are so many types of onions we thought we would take you through some of the most common varieties:

  • Yellow onions are the most common and hold up well to heat. The longer you cook yellow onions, the sweeter they become. They are ideal for long, slow cooking for recipes that call for caramelized onions. They are also called Spanish onions.
  • Red onions have a gorgeous red-purple color and a spicy flavor that is ideal for roasting, grilling and pickling. They are sweet, sharp and assertive. They also are delicious very thinly sliced or pickled, and they can be used in salads or to top tacos, burritos, enchiladas, etc.
  • White onions are strong, sharp onions that are tender, but a bit more strongly flavored than yellow onions. They don't store as well as yellow onions, though.
  • Walla Walla Sweet onions, Vidalias and Mauis have a pale yellow skin, a mild flavor and are so sweet that some people like to eat them raw. They are a great garnish for tacos too due to their high sugar content.
  • Shallots have a mild onion flavor. They are a bulb-shaped allium often used in French vinaigrettes and sauces.
  • Scallions are a long, light and dark green-colored onion and are totally edible. They are great in stir fries, salads and stews. Look for thin ones that have a delicate onion flavor. They can also be used for pickling.
  • Pearl onions, also called boiling onions, are great to use whole in pot pies and stews. They are very small and come in yellow, red and white varieties.
  • Cipollini (or cipolline) onions are a small, flat Italian variety with a buttery texture. Their name literally means "little onion" in Italian. They have a thin skin and have more sugar than most onions. They're also great for roasting and caramelizing, and have a delicious flavor — but can be tricky to peel.
  • Leeks look like large scallions; they have a sweet, tender flavor. I love them in sauces, stews, braises and almost anything.

What To Look For At The Store

Always look for onions that feel heavy, are free of bruises and blemishes, and don’t have a smelly, old-onion scent. When you gently squeeze the onions, they should be firm and tight, not soft or mushy.

Store onions in a cool, dark spot like a cellar or cool pantry. Once cut, you can cover the remaining onion and refrigerate.

Onion dip. (Jesse Costa/WBUR)
Onion dip. (Jesse Costa/WBUR)

Five-Onion Dip

Remember that great dip of your childhood? You sprinkled the dry packet of dehydrated onions into a bowl of sour cream, dipped salty potato chips in, and, well, it was pure comfort food.

My version is made with five types of onions — red onion, sweet Vidalia onions, shallots, leeks and garlic — cooked long and slow so their natural sugars emerge. The caramelized onions are then deglazed with balsamic vinegar and mixed up with sour cream. The result is the same delicious, creamy dip (only way better!), with pure onion flavors and no additives. Serve the dip with potato chips, pita chips or raw vegetables.


  • 3 tablespoons olive oil
  • 2 medium red onions, peeled and very thinly sliced, about 10 ounces
  • 1 large Vidalia onion, about 8 ounces, peeled and very thinly sliced
  • 1 leek, cut lengthwise and thinly sliced, about 6 ounces
  • 1 shallots, peeled and very thinly sliced, about 4 ounces
  • 1 garlic clove, peeled and very thinly sliced
  • Salt and freshly ground pepper, to taste
  • 1/2 cup balsamic vinegar
  • Splash hot pepper sauce
  • 1 cup sour cream


  1. Heat the oil in a very large skillet over low heat. Add the onions, leeks, shallots, garlic, salt and pepper and cook, stirring occasionally, for about 45 minutes. When the onions are soft, golden and sweet, they're ready. Add the vinegar and cook another 15 minutes, stirring frequently. Remove from the heat and let cool slightly.
  2. In the container of a food processor, add the onion mixture with the sour cream and puree until somewhat thick and chunky. Remove, put in a bowl and taste for seasoning; add salt, pepper and hot pepper sauce to taste. Makes about 2 1/2 cups.

Onion Tart With Herbed Crust

This French-style tart combines onions slow-cooked until they are creamy, silky and sweet. The cooked onions are mixed with cream and grated Parmesan cheese and herbs. This is a main-course tart, served with a salad or cut into small squares to serve as a first course or hors d'oeuvre. The crust can be made several days ahead of time.

Serves 4 to 8.

The Herb Pastry

  • 2 cups flour
  • Pinch salt
  • 1 tablespoon fresh rosemary, chopped, or 1 teaspoon dried and crumbled
  • 1 teaspoon fresh chopped thyme, or 1/2 teaspoon dried
  • 1 1/2 sticks butter, cut into small cubes
  • About 1/3 cup ice cold water

The Onion Filling

  • 2 tablespoons olive oil
  • 2 pounds red and yellow onions, very thinly sliced
  • Salt and freshly ground black pepper
  • 1 tablespoon fresh chopped rosemary, or 1 teaspoon dried and crumbled
  • 1 tablespoon fresh chopped thyme, or 1 teaspoon dried
  • 1 cup heavy cream
  • 1 cup grated Parmesan cheese, or Gruyere


  1. Make the pastry: In the container of a food processor, whirl the flour, salt and herbs. Add the butter pieces and pulse about 15 times or until the mixture resembles coarse cornmeal. With the motor running, slowly add the water until the pastry begins to form a ball and comes off the sides of the processor. Don't add extra water or the dough will be too wet.
  2. Remove and wrap into a ball in a piece of wax paper; refrigerate for at least an hour or freeze.
  3. Roll out the dough into a circle and place into a 9-inch round tart pan with a removable bottom. You can also use a pie plate if you don't have a tart pan. Save any pastry scraps to roll out and cut into 1/2-inch wide strips for a lattice topping, if desired. Refrigerate for about 15 to 30 minutes.
  4. Meanwhile make the filling: In a large skillet heat the oil over low heat. Add the onions, salt, pepper and herbs and cook, stirring occasionally, for about 30 minutes. On low heat, add the cream and cook 5 minutes, stirring, or until cream has thickened slightly. Remove from the heat and add the cheese. Let cool slightly.
  5. Add the filling to the pastry. If you had extra pastry and want to roll out strips for a topping, place them on top of the onion filling.
  6. Heat the oven to 400 degrees. While the oven is heating up, place the tart in refrigerator to keep the pastry cool.
  7. Bake on the middle shelf for about 40 to 50 minutes, or until the pastry is golden brown and the filling is bubbling and hot. Remove from oven and let cool about 10 minutes before cutting.

French Onion Soup With Double-Cheese Croutes

This classic French soup is made with beef stock and a heavy blanket of sautéed onions and leeks. You can keep it "light-ish" and serve the soup as is, without the traditional cheese and bread topping.

In Parisian bistros, the onion soup is placed in an ovenproof bowl, topped with a slice of crusty bread and smothered with grated gruyere. I find this method a bit heavy-handed and instead like to make a simple double-cheese croute to place on top of the soup just before serving. The heat of the soup melts the cheese and softens the bread.

If there's any way you can make this soup a day ahead of time, you will be greatly rewarded. The onions, stock and wine all "settle down" overnight and become good friends. This is a main-course soup meant to be served with red wine and a big green salad.

This recipe is adapted from my book "Soup Swap" (Chronicle Books).

Serves 8.


  • 2 1/2 tablespoons olive oil
  • 1 1/2 tablespoons butter
  • 3 pounds onions, yellow and red or just yellow, very thinly sliced
  • 3 large leeks, about 2 pounds, dark green section discarded, and pale green and white sections cut in half lengthwise, washed, and then thinly sliced
  • Salt and freshly ground black pepper
  • 1 1/4 cups dry red wine
  • 1/4 cup Cognac, optional
  • 7 cups beef or chicken stock
  • 8 double-cheese croutes (see below)
  • 1/2 packed cup chopped fresh parsley


  1. In a large soup pot, heat the oil and butter over very low heat. Add the onions and leeks and cook, stirring occasionally, for about 1 hour, or until the onions are buttery and soft but not brown. Season to taste with salt and pepper.
  2. Add the wine and Cognac to the onions and bring to a boil. Simmer vigorously for 3 minutes. Add the stock to the onions and bring to a boil; reduce the heat, partially cover, and simmer about one hour. The soup should be full of flavor; season to taste. If it still tastes weak or too winey, raise the heat, remove the cover and bring to a vigorous simmer for another 5 to 10 minutes.
  3. Serve the soup as is with a sprinkling of fresh parsley. Or, top each bowl of soup with a double-cheese croute.

Double-Cheese Croutes

The term "croute" refers to toasted slices of crusty bread in the shape of an over-sized crouton. These crisp, cheesy croutes are the perfect topping for any soup, but particularly French-style onion soup.

Makes 12 croutes.


  • Twelve 1/4-inch-thick slices of bread from a baguette, sourdough, ciabatta or any loaf of crusty bread
  • 1/4 cup olive oil
  • 1 cup grated Parmesan, Gruyere or any one of your favorite cheeses
  • Freshly ground black pepper


  1. Place a rack as close as possible to the broiler and heat the broiler to high.
  2. Place the bread slices on a cookie sheet. Using a pastry brush or the back of a spoon, brush the toasts with half of the olive oil. Broil for 1 to 2 minutes, or until just beginning to turn golden brown. Remove from the broiler. Sprinkle with half of the cheese and place back in the broiler and broil for another 1 to 2 minutes, or until the cheese is melted. Remove from the broiler and cool for 1 minute.
  3. Gently flip the toasts over and brush with the remaining oil. Broil for 1 to 2 minutes until golden brown. Sprinkle with the remaining cheese and place back under the broiler for another minute, or until the cheese is melted. Serve warm or at room temperature.
  4. The croutes can be made a day ahead of time; cover and place in a tightly sealed tin or plastic bag.

This segment aired on March 11, 2019.


Headshot of Kathy Gunst

Kathy Gunst Resident Chef, Here & Now
Kathy Gunst is a James Beard Award-winning journalist and the author of 15 cookbooks.



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