Easy French Onion Puff Pastry Quiche Recipe

Prep Time: 20 minutes
Cook Time: 50 minutes
Total Time: 1 hour 10 minutes
Servings: 8

Ingredients

For the Puff Pastry Crust

• 1 sheet frozen puff pastry, thawed
• 1 tablespoon all-purpose flour (for rolling)

For the French Onion Filling

• 3 large yellow onions, thinly sliced
• 2 tablespoons unsalted butter
• 1 tablespoon olive oil
• 1 teaspoon sugar
• ½ teaspoon salt
• ¼ teaspoon black pepper
• 2 cloves garlic, minced
• 1 teaspoon fresh thyme leaves (or ½ teaspoon dried thyme)

For the Quiche Custard

• 5 large eggs
• 1 cup heavy cream
• ½ cup whole milk
• 1 teaspoon Dijon mustard
• ¼ teaspoon nutmeg
• ½ teaspoon salt
• ¼ teaspoon black pepper

Cheese

• 1½ cups Gruyère cheese, shredded
• ½ cup Parmesan cheese, grated

Optional Garnish

• Fresh thyme sprigs
• Chopped parsley

Instructions

Step 1: Prepare the Puff Pastry

Preheat your oven to 400°F (200°C).

Lightly flour a work surface and roll the puff pastry sheet into a slightly larger rectangle or circle, depending on your baking dish.

Press the pastry into a 9-inch pie dish or tart pan. Trim any excess dough and prick the bottom lightly with a fork.

Place the dish in the refrigerator while preparing the filling.

Step 2: Caramelize the Onions

Heat the butter and olive oil in a large skillet over medium heat.

Add the sliced onions, sugar, salt, and pepper. Cook slowly, stirring occasionally, for 25–30 minutes until the onions become deeply golden brown and caramelized.

Add the garlic and thyme during the last 2 minutes of cooking.

Remove from heat and allow the onions to cool slightly.

Step 3: Prepare the Custard

In a large bowl, whisk together:

• Eggs
• Heavy cream
• Milk
• Dijon mustard
• Nutmeg
• Salt
• Black pepper

Whisk until smooth and fully combined.

Step 4: Assemble the Quiche

Remove the chilled pastry from the refrigerator.

Spread the caramelized onions evenly across the bottom.

Sprinkle the Gruyère and Parmesan cheeses over the onions.

Pour the egg mixture carefully over the top.

Gently tap the dish on the counter to remove any trapped air bubbles.

Step 5: Bake

Place the quiche on the center rack of the oven.

Bake for 35–40 minutes, or until the filling is set and the top is golden brown.

The center should have only a slight jiggle when gently shaken.

If the pastry edges brown too quickly, cover them loosely with foil.

Step 6: Cool and Serve

Allow the quiche to cool for at least 10–15 minutes before slicing.

Garnish with fresh thyme or parsley if desired.

Serve warm or at room temperature.

Tips for the Best French Onion Quiche

• Take your time caramelizing the onions—the deeper the color, the richer the flavor.
• Gruyère cheese provides the classic French onion flavor, but Swiss cheese also works well.
• Chill the puff pastry before baking to help it stay flaky.
• For extra richness, add a splash of beef broth to the onions while they caramelize.
• Let the quiche rest before slicing for cleaner pieces.

Variations

Bacon French Onion Quiche

Add 6 slices of cooked, crumbled bacon to the filling.

Mushroom French Onion Quiche

Sauté 1 cup sliced mushrooms with the onions.

Vegetarian Herb Version

Add spinach, fresh parsley, and chives for extra flavor.

Three-Cheese Quiche

Use a combination of Gruyère, mozzarella, and Parmesan.

Storage

Store leftover quiche covered in the refrigerator for up to 4 days.

To reheat, warm slices in a 325°F (165°C) oven for about 10 minutes or until heated through.

The quiche can also be frozen for up to 2 months.

Nutrition Information (Approximate Per Serving)

• Calories: 390
• Protein: 13g
• Carbohydrates: 21g
• Fat: 29g
• Fiber: 1g
• Sugar: 4g
• Sodium: 420mg