French Onion Zucchini Bake combines the amazing flavor of caramelized onions, fresh zucchini, and piles of melty gruyere cheese for a side dish that is sure to impress!  If you love French Onion, make sure to check out my homemade French Onion Soup!

Spoonful of French Onions Zucchini Bake
Want to save this recipe?
Just enter your email and get it sent to your inbox! Plus you’ll get new recipes from us every week!

French Onion Zucchini Bake

I seriously love French Onion anything.  (Maybe you noticed my French Onion Soup and French Onion Chicken and French Onion Stuffed Pork Loin?) The flavor of caramelized onions just sort of speaks to me.   Plus, cheese.  What more is there really to talk about?  Zucchini.  We need to talk about that!  The yellow version pictured is also known as summer squash and summertime means that we have an ample supply of it in our garden.

If you have ever grown zucchini you know that it just keeps coming, so we always have a ton of it.  I thought it would be cool to combine one of my favorite summer veggies with the french onion flavors I love so much.  The results: amazing!

Ingredients for French Onion Zucchini Bake

Perfectly caramelized onions.

French Onion Zucchini Bake Recipe

First things first, let’s talk about ingredients.  You will need:

  • Zucchini – (Summer Squash) We obviously prefer to use our garden zucchini, but if you have to purchase at the supermarket, select medium-sized zucchini that are firm and feel heavy for their size. They should be green or yellow with shiny skin.
  • Yellow Onions – There are a ton of different onions to choose from, but I stick with yellow onions because they have a signature sweetness when cooked.
  • Gruyere Cheese – If you are looking to substitute this with a different cheese you want to select one that melts very easily.  I would recommend a Compte’ or Jarlsberg.
  • Butter – We use unsalted in this recipe because we prefer to adjust the salt level by adding kosher salt at the end.
  • Worchestershire Sauce
  • Beef Broth
  • Granulated Sugar
  • Thyme – Fresh thyme can be substituted for dried but you need to adjust the amount.
  • Kosher salt and freshly cracked pepper
French Onion Zucchini Bake with Gruyere Cheese

How to Make French Onion Zucchini Bake

The main step in this recipe that needs attention is the process of carmelizing the onions.  Caramelizing onions is an amazing way to pull out the naturally sweet flavor of a very simple ingredient.  Yellow onions have a natural sweetness that explodes when you slow cook them in butter or oil. The trick here is to take your time.

How to Carmelize Onions

  1. Melt butter in skillet.

  2. Add sliced onion and cook for 3-4 minutes.

  3. Add salt, pepper, sugar, Worcestershire sauce, thyme, and beef broth. Cook until onions are golden brown (about 12 minutes), stirring occasionally to prevent burning.

Finishing the Dish

  1. Add the sliced zucchini and 1 cup of the cheese to the dish and stir to fully combine everything.
  2. Top with the remaining cheese and transfer the pan (covered) to the oven.
  3. Cook covered for 15 minutes and then remove the lid and finish cooking the last 10 minutes (or until the cheese is golden brown and bubbly).
  4. When the dish has finished cooking there will likely be some excess liquid at the bottom of the pan.  Carefully drain this off.
  5. Garnish with fresh thyme and serve!
Baked French Onion Zucchini

What to Serve With French Onion Zucchini Bake

This is an amazing side dish that would work well next to chicken, pork, steak, ham, or even fish.  It is light and full of sweet flavor.  Some recipes that you could naturally pair this with are:

Bite of French Onion Zucchini Bake
French Onion Zucchini Bake
5 from 4 votes

French Onion Zucchini Bake

Prep Time 10 minutes
Cook Time 35 minutes
Total Time 45 minutes
French Onion Zucchini Bake combines the amazing flavor of caramelized onions, fresh zucchini, and piles of melty gruyere cheese for a side dish that is sure to impress!


  • 4 tablespoons unsalted butter
  • ½ teaspoon kosher salt
  • ½ teaspoon pepper
  • 1 tablespoon Worcestershire sauce
  • 1 teaspoon fresh thyme, chopped (plus more for garnish)
  • ½ cup beef broth
  • 8 cups zucchini, seeded and sliced thin (about 2 medium)
  • 2 large yellow onions, sliced thinly
  • 2 teaspoons granulated sugar
  • 2 cups gruyere cheese, shredded and divided


  • Preheat oven to 400°F.
  • Melt butter in a 12-inch oven-safe skillet over medium heat.
  • Add sliced onion to skillet and cook for 3-4 minutes.
  • Add salt, pepper, sugar, Worcestershire sauce, thyme, and beef broth. Cook until onions are golden brown (about 12 minutes), stirring occasionally to prevent burning.
  • Add zucchini to skillet and combine with onions. Add 1 cup of cheese and combine into onion mixture. Top the dish with the remaining cup of cheese.
  • Transfer skillet to oven and bake for 15 minutes covered, remove the lid and cook for an additional 10 minutes or until golden brown.
  • Carefully drain off any excess liquid and top with fresh thyme.

Did you make this recipe?

Thank you for making my recipe! You took pictures, right? Well go ahead and post them on Instagram! Be sure to mention me @iambaker and use the hashtag #YouAreBaker.

Share with your friends!

Categorized in:

Related Recipes

Meet Amanda Rettke

Amanda Rettke is the creator of I Am Baker, and the bestselling author of Surprise Inside Cakes: Amazing Cakes for Every Occasion – With a Little Something Extra Inside.Over the course of her 15+ year blogging adventure, she has been featured in and collaborated with the Food Network, New York Times, LA Times, Country Living Magazine, People Magazine, Epicurious, Brides, Romantic Homes, life:beautiful, Publishers Weekly, The Daily Mail, Star Tribune, The Globe and Mail, DailyCandy, YumSugar, The Knot, The Kitchn, and Parade, to name a few.

Reader Comments

  1. This looks really good. I am counting carbs, and am thinking it might be for me. Any idea of nutrition info?

  2. Love this, whether it’s yellow summer squash OR Zucchini – I have mixed the two vegetables together for this recipe.

  3. What we have here is a severe case of jaundiced zucchini.
    Recipe is well worth a try.
    Thanks for your work and contributions.
    We appreciate you.

  4. This was delicious last night with dinner and this morning using leftovers with an egg on top! I added some French fried onions to the top which made it especially good, but I’m sure it would be superb without them.

    For those who aren’t aware, yes, there is yellow zucchini. It is not often found in grocery stores but a local veggie stand or farmer’s market might have them. I grow them every year in my summer garden & winter greenhouse to keep a constant supply.

Leave a Reply

Your email address will not be published. Required fields are marked *

Recipe Rating

This site uses Akismet to reduce spam. Learn how your comment data is processed.