French Onion Tart Recipe

Introduction

This French Onion Tart combines the rich, sweet flavor of caramelized onions with a creamy savory custard, all nestled in a buttery pastry crust. It’s a simple yet elegant dish perfect for brunch, lunch, or a light dinner. With its comforting flavors, this tart is sure to impress.

Ingredients

• 4-5 medium onions (maximum 2 inches broad)
• 1 sheet shortcrust or puff pastry (*see notes)
• 1 tablespoon butter (for sautéing onions)
• 2 eggs
• 1 cup table cream
• 1 tablespoon dried thyme
• ½ teaspoon salt
• ¼ teaspoon ground black pepper

Instructions

1. Step 1: Peel and slice the onions thinly. Set aside.
2. Step 2: In a bowl, whisk together the eggs, cream, thyme, salt, and black pepper until smooth. Set aside.
3. Step 3: Roll out the pastry dough and place it into a tart pan, trimming any excess from the edges. Use a fork to poke small holes in the base to prevent bubbling while baking.
4. Step 4: Preheat your oven to 400°F (200°C).
5. Step 5: Place a round piece of baking paper fitting the tart base, then add pie weights or dried beans on top. Blind bake the crust for 15 minutes at 400°F (200°C). (*see notes if you prefer to skip this step)
6. Step 6: Melt the butter in a pan over medium heat and sauté the sliced onions until soft and translucent, about 10-15 minutes.
7. Step 7: Spread the cooked onions evenly over the prebaked tart crust. Pour the custard mixture over the onions.
8. Step 8: Bake the tart in the oven at 400-430°F (200-220°C) for 30 minutes until the custard is set and the pastry is golden.

Tips & Variations

• For a richer flavor, caramelize the onions longer until golden brown before adding them to the tart.
• Substitute thyme with fresh rosemary or sage for a different herb aroma.
• Use puff pastry for a flakier crust or shortcrust for a sturdier base—both work well.
• If you want to skip blind baking, prick the crust well and reduce the final baking time slightly to avoid sogginess.

Storage

Store the French Onion Tart in an airtight container in the refrigerator for up to 2 days. Reheat gently in a low oven (about 325°F/160°C) for 10-15 minutes to keep the crust crisp. This tart is best enjoyed fresh but can also be served cold.

How to Serve

Serve this delicious recipe with your favorite sides.

FAQs

Can I use yellow onions instead of other varieties?

Yes, yellow onions are ideal for this tart because they have a natural sweetness that caramelizes well, enhancing the tart’s flavor.

Can I prepare the tart in advance?

You can prepare the onions and custard mixture a day ahead to save time. Assemble and bake the tart just before serving to ensure a crisp crust and fresh custard.

French Onion Tart Recipe

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★★★★★

4.6 from 113 reviews

This French Onion Tart recipe combines the rich, caramelized flavors of sautéed onions with a creamy savory custard baked in a crisp pastry crust. Perfect as an elegant appetizer or light meal, this tart balances a flaky base with a luscious filling seasoned with thyme, salt, and pepper, making it a delightful dish for French cuisine lovers.

• Author: Anna
• Prep Time: 20 minutes
• Cook Time: 45 minutes
• Total Time: 1 hour 5 minutes
• Yield: 6 servings 1x
• Category: Tart
• Method: Baking
• Cuisine: French
• Diet: Vegetarian

Ingredients

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For the Tart Base

• 1 sheet Shortcrust or Puff Pastry (store-bought or homemade, enough to fit a tart pan)

For the Filling

• 4–5 medium onions (each about 2 inches broad), peeled and sliced
• 1 tablespoon butter (for sautéing onions)
• 2 large eggs
• 1 cup table cream
• 1 tablespoon dried thyme
• ½ teaspoon salt
• ¼ teaspoon ground black pepper

Instructions

1. Prepare Onions: Peel and thinly slice 4-5 medium onions and set them aside for later use.
2. Make Savory Custard: In a bowl, whisk together 2 large eggs, 1 cup table cream, 1 tablespoon dried thyme, ½ teaspoon salt, and ¼ teaspoon ground black pepper until smooth and well combined. Set aside this custard mixture.
3. Prepare Pastry Shell: Roll out the pastry dough and fit it into a tart pan. Trim off any excess dough from the edges. Use a fork to prick holes evenly across the pastry base to prevent puffing during baking.
4. Preheat Oven: Preheat your oven to 400°F (200°C) to get ready for blind baking and final baking stages.
5. Bake Pastry Blind: Place a baking sheet cut to fit inside the tart shell and fill it with pie weights or dry beans to weigh down the crust. Bake the crust alone (blind bake) for 15 minutes at 400°F (200°C) to prevent sogginess. This step can be skipped if desired but is recommended.
6. Sauté Onions: Heat 1 tablespoon of butter in a pan over medium heat and sauté the sliced onions until they are soft and lightly caramelized. This usually takes about 10-15 minutes. Stir frequently to avoid burning.
7. Assemble Tart: Spread the cooked onions evenly over the pre-baked tart crust. Then pour the prepared savory custard mixture on top of the onions, distributing it evenly.
8. Bake Tart: Bake the assembled tart in the oven at 400-430°F (200-220°C) for 30 minutes or until the custard is set and the pastry is golden brown. Remove from oven and let cool slightly before serving.

Notes

• You can use either shortcrust or puff pastry depending on your preference for a denser or flakier crust.
• Blind baking the crust is optional but helps avoid a soggy base when adding the moist onion and custard filling.
• Ensure onions are cooked thoroughly to bring out their sweetness and avoid excess moisture in the tart.
• The baking temperature range allows some flexibility depending on your oven; just make sure the custard is fully set and crust is golden.
• This tart pairs wonderfully with a fresh green salad or as part of a brunch spread.

Keywords: French onion tart, savory tart, caramelized onion tart, baked custard tart, French pastry, savory pie