Caramelized Onion and Thyme Quiche

This caramelized onion quiche looks unassuming, but the flavor combination of sweet, slow-cooked alliums and fresh thyme makes it irresistible. This onion quiche recipe is perfect for weekend brunching or casual lunches and dinners. You’ll love that it can be made ahead of time and reheated when you’re ready to serve.

My 93-year old grandmother, Madou, passed away this weekend.  It’s so fresh that I’ve found myself choking up at random thoughts and inopportune moments.  This Caramelized Onion and Thyme Quiche is one of them.  I originally made this for Christmas brunch, because the filling was soft enough for my grandmother to eat and vegetarianwhich meant that her caretaker could enjoy a slice too.

The pictures on the original post were less than stellar, so I remade it a few months ago, reshot it and … did nothing with it.  Until now.  Because the memory hit me so clearly as to why I made it in the first place.  For Madou.  

mixing eggs, milk, cream, nutmeg and pepper for the egg custard.

In fact, many of the quiches on this site were for her.  Because she needed softer foods, but still wanted flavor.  Coming together for a good meal is basically our family’s raison d’être, despite changing dietary habits which simply had to be accommodated.  Caramelized Onion Thyme Quiche definitely fit the bill.

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It also happens that all of the many caretakers who have helped with Madou over the years, are vegetarian.  I became an expert at softening and vegetarian-izing everything.  Soups were always a hit – and my VitaMix blender turned chunky soups into silky smooth purees that were perfect for my grandmother and her assistants – not to mention the rest of the family who would add crunchy garnishes or serve those vegetarian “mains” with a side of ham or chicken…  who am I to judge?

Stirring in the grated gruyere cheese.

A couple of housekeeping notes for you…  The recipe requires blind baking the pastry (essentially, baking the crust before you put the quiche ingredients into it).  The oven temperature to blind bake is higher than the the quiche’s baking temp.  Don’t forget to turn the oven down after baking the crust!  I’m talking to you, Mom!

I am transferring the quiche custard to the blind-baked shell.

I recommend baking the quiche on a foil lined baking sheet to catch any spills.  To make it easier and safer on yourself, place the shell on the baking sheet and then fill it with the quiche ingredientsespecially if you’re using a frozen pastry crust in its own tin.  Sufficed to say that if you hold a liquid-filled aluminum pan by the edges and lift it to transfer to a sheet pan  –  the pan can (and will) sag and even fold in half, like a taco shell — and there goes all your hard work all over the kitchen floor.  (Yeah, it might have happened to me before).

Baked caramelized onion quiche ready to serve.

Let the quiche rest a bit after baking and serve — or let it come to room temperature, then cover and refrigerate until you want to serve it. To reheat,  bring the oven to 300 degrees – and warm the quiche for 20 minutes or so and enjoy with your family! 

When you do, raise a glass to my grandmother, who inspired it.

A slice of caramelized onion quiche.

More quiche recipes you’ll love:

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A slice of caramelized onion quiche on a plate with a fork.
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4.60 from 15 votes

Caramelized Onion and Thyme Quiche

Sweet caramelized onions and fresh thyme make this simple quiche sing!  Great for brunch or lunch entertaining!
Author: Lisa Lotts
Course Breakfast, Main Course
Cuisine American
Keyword caramelized onions, eggs, quiche
Dietary Restrictions Vegetarian
Prep Time 25 minutes
Cook Time 1 hour 45 minutes
Total Time 2 hours 10 minutes
Servings 8


  • 1 9-inch pie crust
  • 2 large onions peeled and thinly sliced
  • 2 tablespoons olive oil
  • ½ teaspoon kosher salt
  • 4 eggs
  • ½ cup milk
  • ½ cup heavy cream
  • ¼ teaspoon black pepper freshly ground
  • ½ teaspoon nutmeg freshly grated
  • 1 tablespoon thyme freshly chopped
  • cups gruyere cheese shredded


  • Preheat oven to 450 degrees.
  • Place pie pastry into glass or ceramic 9″ pie plate. Press bottom and sides into plate and finish the edges of the crust by pressing the tines of a fork against the rim or by pursing the edges together between your thumb and forefinger. Refrigerate crust until oven has heated completely. Place pie plate into the oven and bake for 6-7 minutes until crust is set and just starting to brown. Remove crust from oven and set aside.
  • Reduce oven temperature to 325 degrees.
  • In a large saucepan, heat 2 tablespoons olive oil over medium to medium low heat. Add sliced onions and sprinkle with the salt. Stir and cover. Let the onions caramelize in the pot, stirring occasionally. This may take 40-45 minutes. You don’t have to hover over the pot, just check on it every 7-8 minutes and stir, adjusting heat if too hot or cool. You want the onions to slump after they’ve given off their liquid, then begin to caramelize and brown slightly.
  • While the onions reduce, in a large bowl combine the eggs, milk, cream, black pepper and nutmeg. Whisk to combine.
  • Add the cheese to the egg mixture and stir.
  • When the onions have finished caramelizing, add the thyme to them and stir well.
  • Take a spoonful of the onions and add them to the egg mixture, stirring well. Continue to add the onions to the eggs a spoonful at a time, to temper the egg mixture.
  • Place a piece of aluminum foil on an edged baking sheet. Set the pie shell on top of the foil.
  • Pour the egg mixture into the prepared pie shell.
  • Cut a piece of foil about 10″ square.
  • Place the baking sheet into the oven and carefully set the foil on top of the pie crust (not touching the egg mixture. (this will prevent over browning the crust). Bake for 30 minutes. Remove the foil and continue baking for 15 minutes, until quiche is set.


Reheat leftovers in a low 300°-325° F oven for 10-15 minutes.


Calories: 356kcal | Carbohydrates: 17g | Protein: 12g | Fat: 26g | Saturated Fat: 11g | Cholesterol: 130mg | Sodium: 375mg | Potassium: 166mg | Fiber: 1g | Sugar: 2g | Vitamin A: 640IU | Vitamin C: 4.2mg | Calcium: 306mg | Iron: 1.3mg

Don’t Forget To “Pin It” For Later!

Need a foolproof quiche recipe? This Caramelized Onion and Thyme Quiche is it! A delicious vegetarian entree that you can make-ahead!

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  1. 5 stars
    Hope it tastes as good as it looks! Mine is in the oven.

  2. Could I add the garlic, the traditional sprinkle of cayenne (with the nutmeg), plus a touch of red pepper flakes? My man just had a triple bypass surgery, can’t see him for a bit, but I like my quiches with a jot of a kick lol ????
    Thanks! ??

  3. Ellen Giddings says:

    5 stars
    Waiting for it to come out of the oven now. Smells delish. Thank you for sharing.

    1. I hope you enjoy it, Ellen! Nothing better than something good baking in the oven!

  4. Todd Privitera says:

    5 stars
    Literally picture perfect on my end… The taste exceeded the expectations…. Followed the recipe with no detour of any sort… Thank you. Quite a brilliant and tasty recipe.

    1. I’m so glad it worked for you, Todd. Quiche is so versatile.

  5. 5 stars
    What a lovely tribute to your grandmother, Lisa, and a beautiful picture of the two of you. This quiche sounds so elegant and the filling looks luscious. I love the pairing of gruyere, thyme, and nutmeg. This would be a perfect recipe for a holiday brunch.

    1. Thank you, Amanda – she was a special lady who loved good food!

  6. 5 stars
    I’m so sorry to hear about your grandma Lisa- I don’t have any grandparents left and I miss them 🙁 I’m sure she loved this- it sounds delicious!

  7. 5 stars
    This is such a fabulous recipe. A great tribute to your Grand Mom. Lots of hugs and love your way.

    1. Thank you, so much. The quiche is excellent and Madou enjoyed it.

  8. 5 stars
    Such a beautiful (and tasty-those caramelized onions!!!) way to remember and honor your grandmother! I’m so sorry for your loss. I was getting teary just reading so I can’t imagine how emotional it was to compose this post. It’s so nice of you to think of the caretakers too when bringing food. I’ll be thinking of your sweet grandma and sending you lots of love!

    1. Thank you, Meg! She was a very special lady.

  9. Gabrielle Glatt says:

    What’s beautiful tribute to your grandmothet!

    1. Thank you Gabrielle. It’s been an emotional few days.

  10. Lisa what a beautiful tribute to Madou! I found myself getting choked up reading it. Xoxo

  11. ANN KLEIN says:

    This was delicious!

    1. I’m so glad you enjoyed it, Ann! Thanks for letting me know!

  12. Sharon @ savormania says:

    5 stars
    Onion quiche is my favorite! Can’t wait to try this one with thyme.

    1. It’s a favorite of mine, too! Enjoy, Sharon — let me know how you like it!