Tarte à l’Oignon: A Deliciously Simple French Onion Pie Recipe

Tarte à l’Oignon, or French Onion Pie, is a rustic and deeply flavorful dish that’s surprisingly easy to make. Forget the complicated pastry and fussy techniques – this recipe uses simple ingredients and straightforward steps to create a savory masterpiece that’s perfect for a weeknight dinner or an elegant brunch. This comforting dish features sweet, caramelized onions nestled in a flaky crust, creating a symphony of textures and flavors that will have everyone reaching for seconds. The beauty of Tarte à l’Oignon lies in its simplicity. The star of the show is undoubtedly the onion, slowly cooked to a golden-brown perfection that brings out its natural sweetness. This sweetness is then balanced by savory elements like herbs, cheese, and a buttery crust. It’s a dish that celebrates the humble onion in all its glory.

This recipe is designed to be approachable and achievable for home cooks of all skill levels. We’ll walk you through each step, from selecting the right onions to creating the perfect flaky crust (or using a store-bought shortcut!), ensuring that you’ll have a delicious Tarte à l’Oignon on your table in no time. Whether you’re a seasoned baker or a kitchen novice, this recipe will guide you to a delightful culinary experience.

What is Tarte à l’Oignon?

Tarte à l’Oignon is a classic French dish consisting of a pastry crust filled with caramelized onions, typically seasoned with herbs, butter, and sometimes cheese or cream. It’s a savory tart that showcases the sweetness and depth of flavor that onions develop when cooked slowly. The tart can be served warm or at room temperature, making it a versatile dish for various occasions.

Compared to its cousin, French Onion Soup, the Tarte à l’Oignon offers a different texture and presentation, while retaining the same core flavors. The crust provides a delightful contrast to the soft, caramelized onions, creating a satisfying and complete dish. This makes it a more substantial meal option than the soup, while still providing the comfort and warmth associated with classic French onion flavors.

Why You’ll Love This Recipe

• Simple Ingredients: You likely already have most of these ingredients in your pantry and refrigerator.
• Easy to Make: The steps are straightforward and don’t require any fancy equipment or techniques.
• Incredibly Flavorful: The caramelized onions are the star, providing a sweet and savory flavor that’s simply irresistible.
• Versatile: Serve it as a main course, side dish, appetizer, or brunch item.
• Make-Ahead Friendly: The tart can be assembled ahead of time and baked just before serving.
• Impressive Presentation: It looks beautiful and elegant, perfect for impressing guests.

Ingredients You’ll Need

For the Crust:

• 1 1/4 cups (150g) all-purpose flour: Provides the structure for the crust. Use unbleached flour for the best flavor and texture.
• 1/2 teaspoon salt: Enhances the flavor of the crust and balances the sweetness of the filling.
• 1/2 cup (1 stick, 113g) cold unsalted butter, cut into cubes: The key to a flaky crust. Make sure the butter is very cold.
• 1/4 cup (60ml) ice water: Binds the dough together. Use ice water to keep the butter cold and prevent the gluten from developing too much.
• Alternatively: 1 pre-made pie crust (store-bought, refrigerated)

For the Filling:

• 3 tablespoons olive oil: Used for sautéing the onions. Olive oil adds a nice flavor, but you can also use butter or a combination of both.
• 2 pounds (900g) yellow onions, thinly sliced: Yellow onions are the classic choice for Tarte à l’Oignon. Their flavor becomes sweet and mellow when caramelized. You can also use a combination of yellow and white onions.
• 1 teaspoon salt: Helps to draw out moisture from the onions and speed up the caramelization process.
• 1/2 teaspoon black pepper: Adds a touch of spice to balance the sweetness of the onions.
• 1/4 teaspoon ground nutmeg: Provides a warm, subtle flavor that complements the onions.
• 1 tablespoon fresh thyme leaves: Adds an earthy, herbaceous note to the filling. You can also use dried thyme, but fresh thyme is preferred.
• 1/4 cup (60ml) dry white wine (optional): Adds depth of flavor and helps to deglaze the pan. You can substitute chicken broth or vegetable broth if you don’t have white wine.
• 1 cup (240ml) heavy cream: Adds richness and creaminess to the filling. You can also use half-and-half or milk, but the texture will be less rich.
• 1 egg: Helps to bind the filling together and adds richness.
• 1 cup (100g) Gruyère cheese, grated: Gruyère is a classic cheese for Tarte à l’Oignon. Its nutty, slightly sweet flavor pairs perfectly with the caramelized onions. You can also use other cheeses like Swiss, Emmental, or Parmesan.

Equipment You’ll Need

• 9-inch tart pan with removable bottom: This allows for easy removal of the tart after baking.
• Food processor (optional): For making the crust. You can also make the crust by hand.
• Large skillet or Dutch oven: For caramelizing the onions.
• Rolling pin: For rolling out the dough.
• Parchment paper: For lining the tart pan when blind baking.
• Pie weights or dried beans: To weigh down the parchment paper during blind baking.

Instructions

Making the Crust (From Scratch)

1. Combine dry ingredients: In a food processor, pulse together the flour and salt.
2. Add the butter: Add the cold butter cubes and pulse until the mixture resembles coarse crumbs. The butter should be in pea-sized pieces.
3. Add the water: Gradually add the ice water, pulsing until the dough just comes together. Be careful not to overmix.
4. Form the dough: Turn the dough out onto a lightly floured surface and form it into a disc. Wrap the disc in plastic wrap and refrigerate for at least 30 minutes. This allows the gluten to relax, resulting in a more tender crust.
5. Roll out the dough: On a lightly floured surface, roll out the dough to a 12-inch circle.
6. Transfer to tart pan: Carefully transfer the dough to the tart pan and press it into the bottom and up the sides. Trim any excess dough.
7. Chill the crust: Place the tart pan in the refrigerator for another 15-20 minutes to prevent the crust from shrinking during baking.

Blind Baking the Crust

1. Preheat oven: Preheat oven to 375°F (190°C).
2. Prepare the crust: Line the tart shell with parchment paper and fill with pie weights or dried beans. This will prevent the crust from puffing up during baking.
3. Bake: Bake for 20 minutes.
4. Remove weights: Remove the parchment paper and pie weights.
5. Continue baking: Bake for another 5-10 minutes, or until the crust is lightly golden brown.
6. Cool: Let the crust cool completely before filling.

Making the Filling

1. Caramelize the onions: Heat the olive oil in a large skillet or Dutch oven over medium-low heat. Add the sliced onions, salt, and pepper.
2. Cook the onions: Cook the onions slowly, stirring occasionally, for 45-60 minutes, or until they are deeply golden brown and caramelized. The key to perfect caramelized onions is patience. Don’t rush the process, and make sure to stir them frequently to prevent them from burning.
3. Add flavor: Stir in the nutmeg and thyme. If using, add the white wine and deglaze the pan, scraping up any browned bits from the bottom. Cook for a minute or two until the wine has evaporated.
4. Cool slightly: Remove from heat and let the onions cool slightly.
5. Prepare the cream mixture: In a medium bowl, whisk together the heavy cream and egg.
6. Combine: Stir the cream mixture into the caramelized onions.

Assembling and Baking the Tarte

1. Preheat oven: Preheat oven to 350°F (175°C).
2. Fill the crust: Pour the onion mixture into the cooled, blind-baked tart shell.
3. Top with cheese: Sprinkle the grated Gruyère cheese evenly over the top.
4. Bake: Bake for 30-35 minutes, or until the filling is set and the cheese is melted and bubbly.
5. Cool slightly: Let the tart cool for 10-15 minutes before slicing and serving.

Tips for Success

• Use cold butter for the crust: This is essential for creating a flaky crust.
• Don’t overmix the dough: Overmixing will develop the gluten and result in a tough crust.
• Caramelize the onions slowly: Patience is key! Low and slow cooking will bring out the natural sweetness of the onions.
• Use a mandoline for even slicing: This will ensure that the onions cook evenly.
• Taste and adjust seasoning: Before filling the tart shell, taste the onion mixture and adjust the seasoning as needed.
• Let the tart cool slightly before serving: This will allow the filling to set and make it easier to slice.

Variations

• Add bacon or pancetta: Cooked bacon or pancetta adds a smoky, savory flavor to the tart.
• Use different cheeses: Try Swiss, Emmental, or Parmesan cheese.
• Add garlic: Sauté minced garlic with the onions for extra flavor.
• Add herbs: Experiment with different herbs like rosemary, sage, or oregano.
• Make it vegetarian: Use vegetable broth instead of white wine.
• Use a puff pastry crust: For a lighter, flakier crust, use store-bought puff pastry.

Serving Suggestions

Tarte à l’Oignon can be served warm, at room temperature, or even cold. It’s delicious on its own, but it also pairs well with:

• A simple green salad: The acidity of the salad dressing will cut through the richness of the tart.
• A cup of soup: French Onion Soup, of course! Or try a creamy tomato soup or a light vegetable soup.
• Roasted vegetables: Asparagus, Brussels sprouts, or carrots are all good choices.
• A glass of dry white wine: Such as Sauvignon Blanc or Pinot Grigio.

Make-Ahead Instructions

The Tarte à l’Oignon can be assembled ahead of time and baked just before serving. Here are a few make-ahead options:

• Make the crust ahead: The crust can be made up to 2 days in advance and stored in the refrigerator, wrapped in plastic wrap.
• Caramelize the onions ahead: The caramelized onions can be made up to 3 days in advance and stored in the refrigerator.
• Assemble the tart ahead: Assemble the entire tart (filled and topped with cheese) and store it in the refrigerator for up to 24 hours. Bake as directed just before serving.

Storage Instructions

Leftover Tarte à l’Oignon can be stored in the refrigerator for up to 3 days. Reheat in the oven or microwave before serving.

Recipe Card

Tarte à l’Oignon (French Onion Pie)

Yields: 6-8 servings
Prep time: 45 minutes
Cook time: 1 hour 30 minutes

Ingredients:

For the Crust:

• 1 1/4 cups (150g) all-purpose flour
• 1/2 teaspoon salt
• 1/2 cup (1 stick, 113g) cold unsalted butter, cut into cubes
• 1/4 cup (60ml) ice water
• Alternatively: 1 pre-made pie crust (store-bought, refrigerated)

For the Filling:

• 3 tablespoons olive oil
• 2 pounds (900g) yellow onions, thinly sliced
• 1 teaspoon salt
• 1/2 teaspoon black pepper
• 1/4 teaspoon ground nutmeg
• 1 tablespoon fresh thyme leaves
• 1/4 cup (60ml) dry white wine (optional)
• 1 cup (240ml) heavy cream
• 1 egg
• 1 cup (100g) Gruyère cheese, grated

Instructions:

1. Make the crust: (See detailed instructions above for making the crust from scratch or use a pre-made crust).
2. Blind bake the crust: (See detailed instructions above for blind baking the crust).
3. Caramelize the onions: Heat the olive oil in a large skillet or Dutch oven over medium-low heat. Add the sliced onions, salt, and pepper. Cook, stirring occasionally, for 45-60 minutes, or until the onions are deeply golden brown and caramelized.
4. Add flavor: Stir in the nutmeg and thyme. If using, add the white wine and deglaze the pan. Cook for a minute or two until the wine has evaporated.
5. Prepare the cream mixture: In a medium bowl, whisk together the heavy cream and egg.
6. Combine: Stir the cream mixture into the caramelized onions.
7. Assemble the tarte: Preheat oven to 350°F (175°C). Pour the onion mixture into the cooled, blind-baked tart shell. Sprinkle the grated Gruyère cheese evenly over the top.
8. Bake: Bake for 30-35 minutes, or until the filling is set and the cheese is melted and bubbly.
9. Cool and serve: Let the tart cool for 10-15 minutes before slicing and serving.

Enjoy!

This Tarte à l’Oignon recipe is a guaranteed crowd-pleaser. Its simple ingredients, easy instructions, and incredible flavor make it a perfect dish for any occasion. So gather your ingredients, put on some music, and get ready to create a culinary masterpiece that will impress your family and friends!