French Caramelized Onion Quiche made with red onions, Gruyère, eggs, milk, cream, and a flaky crust for a rich, comforting brunch dish.

The funny thing about this French Caramelized Onion Quiche is that it didn’t start as an attempt to be “fancy” or “classic” or even remotely French. It started because I was cold, hungry, and slightly heartbroken. Isn’t that how a lot of comfort recipes happen? Anyway, a few years ago—actually, closer to five now?—I found myself wandering around Lyon after this long, slightly dramatic family trip. You know those family trips where you swear it’s going to be relaxing, and then two hours in someone cries, someone else gets lost, and you’re just trying to keep everyone from imploding? Yeah. That was the trip.

But there was this one morning, our last day, where things finally slowed down. We found ourselves in a tiny café tucked between a flower shop and a bookstore that smelled like old paper. It was cold outside—one of those mornings where your breath actually shows—and inside they had a few things on the counter: croissants, a tart, and this beautiful, rustic French Caramelized Onion Quiche that didn’t even try to stand out. It just sat there like, “Hey. I’m delicious. Take your time.” So I ordered a slice.

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I remember the first bite so clearly it almost feels ridiculous. The onions were sweet, soft, almost… emotional? (Tell me caramelized onions don’t taste emotional sometimes.) The Gruyère had that nuttiness that feels like winter sweaters and hand-wrapped gifts. The custard was silky in a way that made you close your eyes for a second, like a small pause button on reality. And inside that tiny café—with my family finally not arguing about directions for once and the cold air tucked safely behind the door—it felt like the world suddenly made a little more sense.

So when I got home, in my far less romantic kitchen with a fridge that hums too loudly and a cat who judges me, I tried recreating that French Caramelized Onion Quiche. The first attempt? Burned onions. Second? Crust shrank like it was trying to escape. Third? Too salty. But eventually—eventually—it tasted close enough that I closed my eyes and felt that same pause. That quiet moment. And now, every time I caramelize onions for this quiche, that smell brings me back to that café in a way nothing else does. Maybe it’ll do something like that for you too.

Why You’ll Love This French Caramelized Onion Quiche Recipe?

There’s something about this French Caramelized Onion Quiche that simply works on a deeper level than most savory pies. Part of it is the slow-cooked onions—yes, they take time, and yes, you’ll question your life choices somewhere around minute 25, but trust me, they reward you. They go from harsh and loud to soft, sweet, golden, and almost jam-like. And if you’re anything like me, you’ll catch yourself eating a spoonful straight from the pan and thinking, Wow, this is what growing up tastes like.

Gruyère gives the whole quiche this gorgeous, nutty backbone that makes it feel like something you’d eat on a rainy afternoon with a glass of wine and a questionable sweater choice. And the custard? It’s simple—nothing over-the-top—but when it bakes into the onions and cheese and that golden crust, it becomes something really special. Not “restaurant fancy.” More like “cozy afternoon with someone you love” special.

Plus, quiche just makes you feel… accomplished. Like you did something good today, even if the rest of the day was a mess. Do you agree?

Ingredient Notes:

Let’s talk ingredients—kind of like I’m giving you a little pep talk before you jump into your French Caramelized Onion Quiche adventure.

• Red onions: Sweet and perfect for long, slow caramelizing. They’re the star here.
• Pie dough (pâte brisée): Whether you make it or buy it, go with a buttery, flaky crust. It matters.
• Olive oil: Helps the onions soften and caramelize evenly.
• Balsamic vinegar: Adds that deep, slightly tangy complexity that makes the onions feel grown-up.
• Gruyère: Nutty, melty, and essential for that authentic French vibe.
• Milk + heavy cream: Creates a silky custard without being too heavy.
• Eggs: Holds everything together.
• Nutmeg: A pinch. Just enough. It shouldn’t shout.
• Salt + pepper: Taste and adjust—every onion caramelizes a little differently.

How To Make French Caramelized Onion Quiche?

Okay, let’s make this French Caramelized Onion Quiche. Imagine you’re standing in my kitchen and I’m pointing things out between sips of coffee.

Step 1. Slice your onions
Lengthwise, not in rings. Don’t ask me why—it just works better and they hold their shape.

Step 2. Prep the crust
Roll the dough into a 12-inch circle. Press it into the tart pan, but give it slightly higher sides because it will shrink (mine always does, no matter how confident I feel). Freeze it—30 minutes. Non-negotiable.

Step 3. Blind bake
Line it with foil, add weights, and bake at 350°F for 15 minutes. Cool slightly. Remove foil and weights.

Step 4. Bake again
Prick the bottom with a fork—this keeps it from puffing up—then bake for another 10 minutes. You want a light golden color.

Step 5. Caramelize your onions
This is the heart of the whole recipe. Heat oil, add onions, sprinkle with salt, stir occasionally for about 10 minutes until translucent. Then lower the heat and let them cook. Slowly. Like, “listen to a podcast while you stir” slow. Add balsamic and cook another 10 minutes. They should be deep brown and sweet.

Step 6. Assemble the quiche
Put the tart pan on a baking sheet (trust me). Add half the Gruyère. Add all the onions. Add the rest of the Gruyère.

Step 7. Make the custard
Whisk the eggs, milk, cream, nutmeg, salt, and pepper. Pour over the onions. Don’t stress if it looks full—it settles.

Step 8. Bake
Bake at 350°F for 30–35 minutes until set in the middle. A tiny jiggle is okay. Cool before slicing or it’ll fall apart dramatically.

Storage Options:

This French Caramelized Onion Quiche keeps well in the fridge for 3–4 days. If you reheat it, use the oven—not the microwave—unless you’re okay with a soggy crust (we’ve all done it, no judgment). A low oven around 300°F works perfectly.

Variations and Substitutions:

If you want to switch things up, here are some fun ways to riff on this French Caramelized Onion Quiche:

• Add bacon or pancetta — smoky, salty, delicious.
• Swap cheeses — Swiss or Emmental work great.
• Add mushrooms — earthy and cozy.
• Add herbs — thyme, rosemary, even tarragon if you’re feeling fancy.
• Make it dairy-free — honestly, it works surprisingly well with good substitutes.
• Use shallots for a sweeter, more delicate flavor.

What to Serve with French Caramelized Onion Quiche?

This quiche loves simple, fresh sides that balance its richness.

• A light green salad — lemon vinaigrette is perfect.
• Roasted asparagus — simple and elegant.
• Fresh fruit — something bright like berries or citrus.
• A French baguette — carbs on carbs is sometimes healing.
• Tomato soup — cozy and nostalgic.

Frequently Asked Questions:

Can I use store-bought crust?
Absolutely. No shame. Use it proudly.

Can I make it ahead?
Yes! It reheats beautifully and even tastes better the next day.

Can I change the cheese?
Definitely—Swiss or Emmental are lovely stand-ins for Gruyère.

If you make this French Caramelized Onion Quiche, I genuinely hope it gives you a moment of calm, comfort, or even a tiny spark of joy—kind of like that quiet morning in Lyon did for me. And hey… if you do try it, tell me everything.

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French Caramelized Onion Quiche

Prep Time 25 minutes mins

Cook Time 1 hour hr 45 minutes mins

Total Time 2 hours hrs 10 minutes mins

A rich and elegant French Caramelized Onion Quiche made with sweet slow-cooked onions, Gruyère cheese, and a buttery crust—perfect for breakfast, brunch, or a cozy lunch.

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6 Servings

Ingredients

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For the Quiche

• 2 to 3 large red onions about 1 pound total
• 1 recipe pie dough pâte brisée or prepared pie crust
• 2 tablespoons extra virgin olive oil
• Kosher salt to taste
• Freshly ground black pepper to taste
• 2 teaspoons balsamic vinegar
• 6 ounces Gruyère cheese grated (about 1 1/2 cups)
• 3/4 cup milk
• 1/4 cup heavy cream
• 3 large eggs
• Pinch of ground nutmeg

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Instructions

 

Slice the onions

1. Slice the onions lengthwise—from stem to root—to help them maintain their structure during caramelization.

Prepare the crust

1. If using homemade dough, roll it on a lightly floured surface into a 12-inch circle. Fit the dough into a 9 x 1 1/2-inch tart pan or a 9-inch pie dish, pressing it firmly into the corners. Extend the edges slightly higher than usual to account for shrinkage. Freeze the crust for 30 minutes.

Blind bake the crust

1. Preheat the oven to 350°F (177°C). Line the chilled crust with aluminum foil, pressing it against the sides and leaving enough overhang for easy removal. Fill the crust at least two-thirds full with baking weights such as dried beans, rice, or pie weights.

First bake

1. Bake the crust for 15 minutes. Remove from the oven and allow it to cool briefly. Carefully remove the foil and the weights.

Second bake

1. Prick the bottom of the crust with a fork to allow steam to escape. Return to the oven and bake for an additional 10 minutes or until lightly golden. Transfer to a wire rack to cool.

Caramelize the onions

1. In a large heavy-bottomed sauté pan, heat the olive oil over medium heat. Add the sliced onions and a light sprinkle of salt. Cook, stirring occasionally, for 10 minutes until softened and translucent. Reduce heat to medium-low and cook for an additional 40 minutes, stirring occasionally, until deeply browned. Add the balsamic vinegar and cook for 10 minutes more, until fully caramelized. Remove from heat.

Assemble the quiche

1. Place the tart pan on a baking sheet to catch any overflow. Sprinkle half of the Gruyère cheese evenly over the prepared crust. Spread the caramelized onions over the cheese, then top with the remaining cheese.

Prepare the custard

1. In a medium bowl, whisk together the milk, heavy cream, and eggs. Season with nutmeg, salt, and pepper. Pour the custard mixture over the onion and cheese layers.

Bake the quiche

1. Transfer the quiche to the 350°F oven and bake for 30–35 minutes, or until the center is just set. Cool on a wire rack for 10–15 minutes before slicing and serving.

Notes

To make this French Caramelized Onion Quiche gluten-free, simply replace the traditional pie dough with a certified gluten-free pie crust. Ensure that the Gruyère cheese and balsamic vinegar are also labeled gluten-free, as some brands may contain additives. All other ingredients in the recipe are naturally gluten-free.

Bitty

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Bitty

I’m Bitty, owner of nodashofgluten.com, where I share simple, delicious recipes for all tastes, including gluten-free. Check out my “About Me” page for more info!

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