Caramelized Fennel and Onions

Side DishGluten-FreeVegetarianOnion

Sliced onions and fennel, slowly cooked until lightly browned, tossed with Parmesan, lemon, and parsley.

Photography Credit: Elise Bauer

Fennel lovers, onion lovers, unite!

And then take a shower in grated Parmesan, lemon zest, and chopped parsley.

I’d like to say this is quick and easy, but it’s not quick. It’s long and easy, the sort of thing you can just put on the stove and give a stir every once in a while, as you cook the rest of the meal.

The onions and fennel are only lightly caramelized. You could cook them longer if you wanted, or sprinkle some sugar on them to bring out more of the caramelization.

But just cooking them down and lightly browning them, and then tossing them with everything else, works for me. Wonderful flavors. Terrific alongside grilled fish or chicken.

Caramelized Fennel and Onions Recipe

  • Prep time: 10 minutes
  • Cook time: 1 hour
  • Yield: Serves 4


  • 2 large onions, halved then sliced lengthwise (root to tip) in 1/4-inch thick slices
  • 2 large fennel bulbs, sliced into 1/4-inch thick slices
  • 1/4 cup olive oil
  • 1 Tbsp butter
  • Salt
  • 1/4 cup grated Parmesan
  • 2 Tbsp chopped fresh parsley
  • 1 teaspoon lemon zest
  • 2 teaspoons lemon juice


1 Cook fennel and onions in olive oil and butter: Heat olive oil and butter in a large, uncovered, wide pan on medium high heat. Add the sliced fennel and onions and stir to coat. Stir occasionally.

After about 10 minutes, sprinkle the onions and fennel with salt. Lower the temperature to medium.

You want to strike a balance between allowing the pan to get hot enough so that some caramelization (when the natural sugars in the onion and fennel start to brown) and keeping the pot from getting so hot that the onions and fennel dry out.

If it becomes an issue, you can add a couple tablespoons of water to the pan to help the onions and fennel to keep from drying out too much.

2 Scrape up browned bits: Stir occasionally, scraping up any browned bits from the bottom of the pan. Note that the browned bits are the tastiest parts.

Cook for another 30 minutes to an hour, depending on how much of a hurry you're in, and how caramelized you want your mixture to be. The longer you cook, the more caramelized and browned.

Taste test along the way to see if the cooking has been sufficient for your taste.

By the way, the onions and fennel will have plenty of flavor without having to be completely cooked down and browned all over.

3 Toss with Parmesan, parsley, lemon: When ready to serve, remove from heat and toss in the freshly grated Parmesan cheese, the chopped parsley, lemon zest and lemon juice. Taste and add more lemon juice if necessary.

Serve alone as a side to chicken or seafood, or on crackers or thinly sliced toasted baguette for a crostini. You can also use it as a filling for a rustic tart.

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How to Slice an Onion

Showing 4 of 17 Comments / Reviews

  • ramona dupre'

    I love liver with onions. How do you cook the onions?

  • Vikker

    I am so making this to go with the Roast chicken we are having tonight.

  • Sharkey

    Looks great. I have friends who make a great caramelized onion quiche out of Julia Child’s cookbook. Would this combination of fennel and onion work in a quiche?

    It would work great in a quiche! ~Elise

  • Elisha

    I LOVE fennel- raw or cooked- but my husband hates it. Every few months I try making it a different way but it doesn’t seem to help – it’s the anise flavor that gets him. Sigh. It’s the same way with mint, and with the summer upon us I dream about fresh mint in drinks, salads and dessert.

    Hi Elisha, my father hates fennel too. But when I served him some of this, he went back for seconds. He loved it. ~Elise

  • laura @ glutton for nourishment

    i *adore* fennel, and i *adore* caramelized onions (or caramelized anything for that matter). this might be a little unorthodox, but i’m thinking this would be great as a burger topping at our memorial day bbq…

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