Onion Tart Recipe

When I first discovered the Onion Tart Recipe in the charming villages of Provence, France, I immediately understood why it’s such a beloved dish in French cuisine.

Known locally as Tarte à l’Oignon, this savory pastry captures the rustic charm of southern France simple ingredients elevated through patience and technique.

The golden crust, layered with caramelized onions and fragrant herbs, reflects the heart of Provençal cooking: seasonal, aromatic, and deeply satisfying.

Every bite feels like a journey through the sun-soaked countryside of southern France. 

Ingredients

Here are the ingredients you’ll need to create this savory and impressive tart. Using high-quality, fresh ingredients will make all the difference in the final flavor.

• 2 cups all-purpose flour – This forms the base of our tender, flaky pastry crust.
• 1/2 tsp kosher salt – Essential for bringing out the flavors in both the pastry and the topping.
• 1 Tbsp sugar – A small amount of sugar in the pastry helps with browning and adds a subtle depth.
• 12 Tbsp cold unsalted butter, diced – Use very cold butter, cut into small pieces, for the flakiest possible crust.
• 1/2 cup ice water – Ice-cold water is crucial to keep the butter from melting, ensuring a tender pastry.
• 1 cup gruyère cheese, shredded – Freshly shredded gruyère melts beautifully and has a nutty flavor that is classic with onions.
• 1 1/2 tsp fresh thyme, minced – Fresh thyme provides a lovely, earthy aroma that is much better than dried.
• 2 tsp fresh chives, minced – Adds a delicate, mild onion note that complements the sweet onions.
• 1 1/4 lbs sweet onions (about 3 medium) – Sweet varieties like Vidalia or Walla Walla work best as they caramelize beautifully.
• 1 Tbsp heavy cream – Brushing the onions with cream adds richness and helps them brown nicely.
• 3 Tbsp unsalted butter, diced – Dots of butter on top melt over the onions, adding flavor and moisture.
• 1 tsp kosher salt – To sprinkle over the onions before baking, enhancing their natural sweetness.

Note: This recipe yields one large tart, which provides several servings when cut into appetizer-sized squares.

Variations

While this classic French-inspired tart is delicious on its own, you can easily tweak it to suit your preferences or what you have available.

• Cheese Swaps: If you don’t have gruyère, other good melting cheeses like Swiss, fontina, white cheddar, or even a mix of parmesan and mozzarella would work well.
• Herb Variations: Feel free to swap the thyme and chives for other herbs. Rosemary would add a lovely piney note, or a bit of sage could bring a warm, earthy flavor.
• Add a Savory Jam: For a touch of sweet and savory complexity, spread a very thin layer of fig jam or bacon jam over the pastry before adding the cheese and onions.
• Use Puff Pastry: If you’re short on time, you can substitute a sheet of store-bought all-butter puff pastry for the homemade crust. Just be sure to follow the package directions for baking.

Cooking Time

• Prep Time: 30 minutes
• Resting Time: 1 hour (for the dough)
• Cook Time: 40 minutes
• Total Time: 2 hours 10 minutes

Equipment You Need

• Food Processor: This makes creating the pastry dough quick and effortless, perfectly cutting the butter into the flour.
• Rolling Pin: To roll the chilled dough into a neat, even rectangle.
• Baking Sheet: A standard baking sheet is the perfect vessel for baking this free-form tart.
• Parchment Paper: This prevents the tart from sticking to the pan and makes for easy cleanup.
• Ruler and Knife: For trimming the dough to a clean 10×14 inch rectangle, giving the tart a professional look.

How to Make Onion Tart Recipe?

This recipe looks impressive but is deceptively simple to execute. The magic happens in the oven, where the raw onions bake directly on the tart, becoming sweet and tender without any pre-cooking required.

Step 1: Prepare the Pastry

In the bowl of a food processor, combine the flour, salt, and sugar. Pulse it a few times to mix everything together. Add the cold, diced butter and pulse about 10-12 times, just until the butter is the size of small peas. With the machine running, pour the ice water through the feed tube and pulse only until the dough begins to form a ball. Don’t overmix.

Step 2: Chill the Dough

Turn the dough out onto a lightly floured surface and gently knead it once or twice to bring it together. Form it into a ball, wrap it tightly in plastic wrap, and refrigerate it for at least one hour. This chilling step is crucial; it allows the gluten to relax and the butter to firm up, which will result in a tender and flaky crust.

Step 3: Assemble the Tart

Preheat your oven to 400°F and line a baking sheet with parchment paper. On a lightly floured surface or between two sheets of wax paper, roll the chilled dough into a rectangle slightly larger than 10×14 inches. Use a ruler and a small knife to trim the edges for a clean rectangle. Place the dough on the prepared baking sheet. Sprinkle the shredded gruyère cheese evenly over the dough, followed by the minced thyme and chives.

Step 4: Bake and Serve

Peel the onions, cut them in half, and slice them very thinly into half-moons. Arrange the onion slices in overlapping diagonal rows across the pastry. Lightly brush the onions with heavy cream, dot the top with the diced butter, and sprinkle with kosher salt. Bake for about 40 minutes, or until the crust is golden brown and the onions are tender and caramelized. Let it cool slightly on the pan before cutting it into squares to serve.

🇫🇷 Journey Through France: The Charm of the Provençal Onion Tart

Traveling through southern France, especially the picturesque region of Provence, I fell in love with the humble yet elegant Tarte à l’Oignon (Onion Tart). This dish beautifully represents the French philosophy of turning simple ingredients into something extraordinary. The tart’s golden crust and caramelized onions embody Provence’s sun-drenched fields and rich culinary traditions. Though enjoyed across France, it’s especially cherished in Provence and Alsace, where local onions and cheeses give it their signature rustic, flavorful character. 

Additional Tips for Making this Recipe Better

Through making this tart a few times, I’ve found a couple of small things that make a big difference.

• Slice Onions Evenly: I try to slice my onions as uniformly as possible using a mandoline or a very sharp knife. This helps them cook at the same rate and ensures that none of them are undercooked or burnt.
• Don’t Be Shy with Salt: The final sprinkle of kosher salt over the onions before baking is more important than you’d think. It helps draw out their moisture and intensifies their sweetness as they roast.
• Watch the Edges: Ovens can have hot spots. If I notice the edges of my tart are browning too quickly, I loosely cover them with strips of aluminum foil for the last 10-15 minutes of baking. This protects the crust while the onions finish cooking.

How to Serve Onion Tart?

In France, especially in the regions of Provence and Alsace, this onion tart is often enjoyed as a light meal or elegant appetizer. Locals serve it warm or at room temperature, paired with a crisp glass of white wine or a refreshing Provençal rosé. For a more complete experience, it’s often accompanied by a simple green salad with vinaigrette. Whether served at a countryside picnic or a Parisian café, it brings authentic French charm to every bite. 🇫🇷

Make Ahead and Storage

This recipe is very convenient for planning ahead, whether you’re prepping for a party or just want an easy meal.

Make Ahead: The pastry dough can be made up to 2 days in advance and kept well-wrapped in the refrigerator. You can also freeze the unbaked dough for up to a month; just let it thaw in the refrigerator before rolling it out.

Storing: Leftover tart can be stored in an airtight container in the refrigerator for up to 3 days. The crust will soften slightly but the flavor will still be fantastic.

Reheating: To revive the crust’s crispness, reheat slices on a baking sheet in a 350°F oven for about 5-10 minutes, or until warmed through. I avoid the microwave, as it can make the pastry tough and soggy.

Nutritional Information

Here is an estimated nutritional breakdown for one serving of the onion tart.

• Calories: 345 kcal
• Protein: 4g
• Carbohydrates: 32g
• Fat: 22g

Why You’ll Love This Recipe?

This French onion tart is bound to become a new favorite for so many reasons.

• Elegant Yet Easy: It has the look and taste of a fancy bakery item, but the steps are surprisingly simple. The food processor does most of the work for the crust, and there’s no need to pre-cook the onions.
• Amazing Flavor Combination: The buttery, flaky crust, nutty gruyère cheese, and sweet caramelized onions create a classic flavor profile that is absolutely irresistible. It’s sophisticated comfort food at its best.
• Perfect for Entertaining: Since it can be made ahead and tastes just as good at room temperature as it does warm, this tart is an ideal appetizer for any gathering. It takes the stress out of party prep.
• Versatile Serving Options: You can cut it into small squares for a finger-food appetizer or serve larger slices with a side salad for a chic brunch or light lunch. It’s a recipe that works for many different occasions.