Apple and Caramelized Onion Tart

A recipe for an Apple and Caramelized Onion Tart! This tart has a buttery, flaky crust filled with caramelized onions, Alpine cheese, a savory custard, and thinly sliced apples.

Brunch Week

Welcome to the #BrunchWeek! We are so excited to have you join us this year as we celebrate.

Bloggers from around the country are showcasing their best brunch dishes, from cakes and breakfast breads to tarts and quiche – there is something for everyone.

I am joining in on the second day of Brunch Week with an Apple and Caramelized Onion Tart. Check out what else I made this week:

• Macaroni and Cheese Soufflé
• Chocolate Beghrir (Algerian Chocolate Honeycomb Pancakes)
• Teh Tarik (Malaysian Pulled Tea)
• Lemon Blueberry Parfait

Apple and Caramelized Onion Tart

I am bringing a little fall flavor to Brunch Week with this Apple and Caramelized Onion Tart!

An elegant addition to the brunch table and seasonal celebrations, the tart comes together by filling a basic pie crust with shredded Alpine cheese, caramelized onions, a savory custard mixture, and thinly sliced apples.

Once assembled, the apples are brushed with a little melted butter and sprinkled with sugar before baking in a 400˚F (200˚C) oven until puffed and golden.

Allow to cool for about 5 minutes, then remove from the pan and enjoy warm or allow the tart to cool to room temperature before slicing.

Forming the Pie Crust

For the base of the tart, I used a homemade pie crust. You can also swap for a favorite store-bought pie crust, if desired.

Do not pack in the flour when measuring or you may end up with too much. To measure flour, gently spoon it into the measuring cup and level with a knife without pressing down. The most accurate way to measure is by weight.

To help create the buttery flaky texture, I generally use a dough blender to cut in the well-chilled, diced butter. You can also use two forks or the tips of your fingers. Make sure the butter is cold and try to work as quickly as possible to keep it from melting.

Only add enough water to bring the dough together. You may not need the full 1/3 cup (80 millimeters) or you may need a little more depending on how you measured the flour. If the dough is still too crumbly the come together, slowly add a little more water.

After forming the pastry dough, allow it to rest in the refrigerator for 30 minutes to 1 hour. The dough is delicate and this will make it easier to roll and handle. If the dough is still too warm, place back in the refrigerator for a few more minutes.

You can prepare it ahead of time and refrigerate for up to two days, but the dough may be too cold to immediately roll. Leave on the counter for a few minutes before handling if chilling for longer than an hour.

After pressing the dough into the prepared tart pan, place the pan in the refrigerator while the oven preheats to keep it cold. Blind bake (bake the dough without the filling) with parchment-lined pie weights or uncooked rice before assembling.

A Few More Apple and Caramelized Onion Tart Tips

For the updated photos (2025), I used a 14 x 4.75 inch (36 x 12 centimeter) rectangular tart pan with a removable base. You can also assemble the ingredients in a 9 inch (23 centimeter) round tart pan or even divide the ingredients among individual 4.75 inch (12 centimeter) tartlet pans.

For the Alpine cheese, I generally use Gruyère or Emmentaler. After shredding, toss in a little flour. This will create a barrier between the moisture in the ingredients and the crust.

To caramelize the onion slices, cook over low to medium low heat until a deep golden color and softened. Don’t rush the process by turning the heat up. It takes time for the flavor to develop, around 30-45 minutes.

If you want a little less onion flavor, drop the amount down to 1-2 onions and 1 tablespoon butter/1 tablespoon olive oil (the combination of butter and oil helps keep it from burning).

I did not peel the apples before slicing. I personally love that strip of red (or green) to add contrast across the top of the tart. You can peel the apples if desired.

If the crust along the sides of the tart pan gets too dark before the center has a chance to fully cook, cover the edges with foil and drop the temperature down to 375˚F (190˚C).

Allow the tart cool in the pan for about 5 minutes before carefully removing and serving warm or at room temperature. Once cooled, refrigerate leftovers in an airtight container for up to 3 days.

Check out what everyone else made:

• Baked Apple Cinnamon Doughnuts by The Chef Next Door
• French Toast with Apple Compote and Caramel Syrup by The Redhead Baker
• Fiddlehead, Sun-Dried Tomato and Basil Quiche by Palatable Pastime
• Poached Eggs on Asparagus Bundled with Prosciutto on Cheesy Polenta by Culinary Adventures with Camilla
• Baked Seafood Stuffed Avocados by Rants From My Crazy Kitchen
• Kielbasa Welsh Rarebit by A Day in the Life on the Farm
• Pulled Pork Pancakes by Ketchup with Linda
• Sausage and Fried Apples by Making Miracles
• Lemon Meringue Angel Food Cake by Love & Confections

This recipe was originally posted in May 2016 and updated in August 2025.

Apple and Caramelized Onion Tart Recipe

Adapted from from Pastry Chef Online and Spice Roots

Print Pin

Apple and Caramelized Onion Tart

A recipe for an Apple and Caramelized Onion Tart! This tart has a buttery, flaky crust filled with caramelized onions, Alpine cheese, a savory custard, and thinly sliced apples.

Course Side Dish

Cuisine N/A

Keyword apple, apple pie, caramelized onion, cheese, fall, onion, pie, tart

Prep Time 20 minutes minutes

Cook Time 1 hour hour 10 minutes minutes

Resting Time: 1 hour hour

Total Time 2 hours hours 30 minutes minutes

Servings 1 Tart

Ingredients

Crust:

• 1 1/2 cups (190 grams) all-purpose flour
• 1 tablespoon (12 grams) granulated sugar
• 1/2 teaspoon salt
• 6 tablespoons (85 grams) unsalted butter chilled and diced, plus more for greasing
• 1/3 cup (80 milliliters) cold water

Caramelized Onions:

• 2 tablespoons (28 grams) unsalted butter
• 1 tablespoon (15 milliliters) olive oil
• 3 large onions peeled, cut in half, and thinly sliced
• 1 sprig fresh thyme
• salt and freshly ground black pepper to taste

Assembling the Tart:

• 3 ounces (85 grams) Alpine cheese such as Gruyère or Emmentaler, shredded
• 1/2 tablespoon all-purpose flour
• 2 large eggs
• 1/4 cup (60 milliliters) heavy cream
• 1/4 teaspoon salt
• pinch freshly ground black pepper
• pinch freshly grated nutmeg
• 2 apples cored and thinly sliced
• 1 tablespoon (14 grams) unsalted butter melted
• coarse sugar for sprinkling, optional

Instructions

To make the crust:

• In a large bowl, combine the flour, sugar, and salt.
• Quickly cut in the cold butter using a dough blender, two forks, or your fingers until blended and no pieces are larger than a pea and the dough has a crumbly texture.
• Slowly add the cold water to form a soft and smooth dough.
• Form the dough into a disc, wrap in plastic, and refrigerate until chilled, 30 minutes to 1 hour or up to two days.

To make the caramelized onions:

• In a wide pot or saucepan, melt together the 2 tablespoons (28 grams) butter and olive oil over medium heat.
• Once the butter is melted, add the onions and cook, stirring occasionally, until deeply golden and caramelized, about 30 minutes. Adjust heat between medium and low as needed to caramelize the onions without burning.
• Season with the leaves from the thyme sprig, salt, and freshly ground black pepper.
• Remove from heat, transfer the caramelized onions to a bowl, and allow to cool to room temperature.

To assemble:

• Grease a 14 x 4.75 inch (36 x 12 centimeter) rectangular tart pan or 9 inch (23 centimeter) round tart pan with removable base with butter.
• Remove the chilled dough from the refrigerator and roll on a floured surface into a thin sheet large enough to completely cover the bottom and sides of the pan, about 1/8 inch (3 millimeters) thick.
• Carefully transfer the sheet to the prepared pan, gently pressing down along the bottom and sides to make sure it is completely covered without any air bubbles. Cut away any excess scraps.
• Prick across the bottom of the tart with a fork, then place the pan in the refrigerator to chill while the oven preheats.
• Preheat oven to 400˚F (200˚C).
• Once preheated, remove the pan from the refrigerator and place on a rimmed baking sheet (to protect the oven just in case any butter seeps through the bottom or anything bubbles over).
• Cover the crust lightly with a sheet of parchment and fill with ceramic pie weights or uncooked rice. Bake in the preheated oven until starting to set, 10-15 minutes.
• Carefully remove the parchment sheet with the weights from the crust and allow the crust to cool slightly.
• In a small bowl, toss the shredded cheese with the flour until evenly coated.
• Sprinkle the coated cheese across the bottom of the partially baked crust.
• Cover the cheese with an even layer of the caramelized onions.
• In a medium bowl, whisk together the eggs, heavy cream, salt, pepper, and nutmeg until evenly blended.
• Pour the mixture into the tart pan in an even layer over the caramelized onions.
• Arrange the thin apple slices slightly overlapping across the top of the tart.
• Gently brush the top of the apple slices with melted butter and, if desired, sprinkle with coarse sugar.
• Bake in the 400˚F (200˚C) oven until the egg mixture is puffed and the apple slices are lightly golden, about 25-30 minutes.
• Allow the ingredients to settle in the tart for 5 minutes before carefully removing from the pan.
• Serve warm or at room temperature.