This delicious Provençal French onion tart has a 2-ingredient filling of braised onions mixed with eggs, baked in a mustard-coated pie shell – a fantastic recipe for brunch or a Mediterranean inspired dinner
Onions are one of my favorite foods, and this simple French onion tart showcases the best of their tender sweet side. First they’re braised with just a little oil and water and salt to soften them and coax out their natural sugars. Then they’re mixed with eggs and loaded into a flaky tart shell coated with dijon mustard. A decorative arrangement of thyme sprigs and Niçoise olives on top gives it a lovely French country look.
It’s a beautiful brunch dish. I’ve also served it dinner (to my book group), with grilled Aleppo pepper chicken and ratatouille (Julia Child’s recipe).
As much as I love this onion tart recipe, I always cry my eyes out cutting all those onions. I really need to buy onion goggles. Did you know that If not for tears, the chemicals in onions could damage your eyes? Years ago, when I worked for ABC News 20/20, I produced a segment on crying. I visited a scientist in Minnesota named Dr. William Frey, who was studying the chemical composition of tears. He gave people test tubes to collect their irritant tears and emotional tears so he could study the differences.
First he’d sit them in a screening room and show them a tear-jerker of a scene from an old Jimmy Stewart movie to gather their emotional tears. Then he’d have them lean over a blender full of freshly-pureed onions, to collect their irritant tears. Dr. Frey’s fascinating discovery was finding chemicals in emotional tears that were not present in irritant tears. His research has continued to prove that the reason we feel better after a good emotional cry is we’re literally ridding our bodies of toxins associated with stress.
It’s nice to know that whether you’re crying because you’re making this French onion tart or because of something sad or stressful, tears are beneficial.
Big thanks to my friend Diane Rao for this recipe. She’s an expert on all things French. If you’re planning a trip to Paris, you should check out her Instagram: for some great ideas and inspiration.
Many years ago Diane gave me a cookbook called A Passion for My Provence, which is my source for this “Tarte campagnarde a l’oignon.”
I hope you enjoy this tart. And if you find a way, other than goggles, to get through this recipe without crying your eyes out, I would like to know your secret.
If you try this recipe I hope you’ll come back to leave a comment and rating. I’d love to know what you think.Print
French Onion Tart
Naturally sweet braised onions baked in a mustard-coated tart shell, topped with thyme and olives. Perfect for brunch.
- Prep Time: 2 hours
- Cook Time: 1 hour
- Total Time: 3 hours
- Yield: 8 1x
- Category: Side dish
- Method: Bake
- Cuisine: French
For The Tart Shell
- 1 stick cold unsalted butter
- 1 cup unbleached all-purpose flour
- 1/4 teaspoon salt
- 3 tablespoons cold water
For The Filling
- 3 tablespoons olive oil
- 4 large onions, thinly sliced (about 6 cups)
- 1 teaspoon salt
- 2 eggs, whisked
- 1 tablespoon dijon mustard
- 5–6 thyme sprigs
- 6–8 Niçoise olives
- Make The Tart Shell Cut butter into small chunks and put it into the bowl of a food processor fitted with the s-shaped chopping blade. Add flour, and salt. Pulse about 10 times. Then add the water and pulse about 10 more times or until the texture resembles cornmeal. Pour the mixture onto a clean surface and, using the heal of your hand, press it little by little, until the butter and flour are incorporated. Gather it into a ball. Flatten the ball into a disc. Cover with wax paper and refrigerate for 15 minutes, to firm it up a bit. Generously dust your work surface and rolling pin with flour to prevent sticking. Remove the dough from the fridge and roll it into a 13-inch circle. Line a 9 or 10-inch tart pan with the dough, trimming off the excess. Make several pricks in the bottom with a fork and refrigerate for 2 hours. (It can also be frozen until you’re ready to use it)
- Preheat oven to 400ºF. Cover the tart shell with foil and fill the bottom with dried beans. Bake it in the middle of your oven for 10 minutes. Remove the beans and foil and bake for another 5-10 minutes. You want the bottom to dry without coloring.
- Make The Tart: Preheat the oven to 425ºF. In a large dutch oven or heavy pot combine olive oil, sliced onions, salt and 1/4 cup of water. Heat the mixture until it starts to sizzle, then turn the heat down to a simmer, cover, and cook for 30 minutes, stirring occasionally. Spoon onions into a medium bowl and set aside to cool. Pour off liquid that has accumulated around the onions and combine eggs with onions. Spread mustard over the bottom of the pre-baked tart shell, using a pastry brush. Spread the onion mixture evenly on top. Make a pretty pattern on top with the thyme sprigs and olives. Bake in the middle shelf of the oven for 30-40 minutes, until the top is golden brown. Serve at room temperature, cut into wedges.
To make this recipe quick and easy, use a store-bought pie crust.