This onion tart recipe has a custard base that is loaded with caramelized onions, bacon, and fresh herbs. It’s baked in a flaky pie crust until golden brown to create this unique and versatile savory tart.
I love to serve this Caramelized Onion Tart with Lemon Parmesan Salad for brunch, lunch or a light dinner.
I made his yummy onion tart for my family awhile back and found myself back in my kitchen baking another one less than two weeks later.
It’s so unique and SO delicious. And, I love that it works for any meal from brunch to dinner.
The flavor of sweet, caramelized onions combined with bacon and a hint of fresh sage and thyme is so familiar and comforting that we all instantly fell in love.
Table of contents
Ingredient Notes
- Unbaked pie crust – Do yourself a favor and use a store-bought refrigerated pie crust. For pie recipes, I always make my Food Processor Pie Crust recipe but a sturdy refrigerated crust (like Pillsbury) works really well for this onion tart recipe.
- Bacon slices – Regular thickness (not thick-cut) cut into ½-inch pieces.
- Butter
- Sweet yellow onions – Look for yellow onions labeled “sweet”. Varieties of sweet yellow onions include Vidalia, Walla Walla, and Maui. They contain more sugar than other onions which makes them better for caramelizing.
- Kosher salt and freshly ground black pepper
- Eggs
- Sour cream – You can substitute crème fraiche but it is a more expensive choice and sour cream works very well.
- Fresh sage and thyme – Just enough to add a hint of herby flavor but not overwhelm the yummy caramelized onions.
- Ground nutmeg
How to Make an Onion Tart
Caramelize the Onions
- Cook the bacon in a large skillet over medium-high heat, stirring frequently, until crisp. Use a slotted spoon to transfer the bacon to a double layer of paper towels to drain. Leave the bacon drippings in the skillet. Reduce heat to medium and melt the butter with the drippings.
- Add the onions and salt and cook, stirring frequently, for 5 minutes. Cover and cook for about 8 to 10 minutes, stirring every 2 minutes or so and then covering again, until the onions are soft and golden brown. If the onions begin to burn, reduce the heat as needed,
- Uncover the skillet and cook for an additional 2 to 3 minutes or until deep golden brown and any liquid in the skillet has evaporated. Remove the skillet from the heat and allow the onions to cool.
This shortcut method for caramelizing onions takes less than 20 minutes. This is less than half the time of traditional methods.
Parbake the Crust
- Coat the bottom and sides of a nonstick 9-inch tart pan with a removable bottom with nonstick cooking spray. Set the pie crust down, centering it in the prepared tart pan.
- Press it down across the bottom and up the sides of the pan, pressing it into the grooves of the tart pan. If you have a slight overhang of crust around the top edge of the pan, fold it over (towards the inside of the pan) and then press it flat against the sides.
- Lightly prick the bottom of the crust all over with a fork.
- Press a sheet of aluminum foil down across the bottom and against the edges of the crust, pressing it into the fluted edges of the dough. Fill the foil with pie weights or dry beans and place the tart pan on a baking sheet (for easy transport in and out of the oven). Bake in a preheated 400 degree F oven for about 15 minutes, or until dry (you can lift the foil and peek at the bottom of the crust).
A bag (or two) of dry beans is an inexpensive stand-in for pie weights. It works great! I keep a container in my pantry with dry beans that I use over and over again for this purpose.
Make the Onion Tart Filling and Bake
- In a medium bowl, whisk the eggs with the sour cream until smooth. Whisk in the sage, thyme, remaining salt, pepper, nutmeg, and bacon.
- Stir in the cooled onions.
- Pour the mixture in the prepared crust.
- Bake in a preheated 400 degrees F oven for 25 to 30 minutes or until set in the center and golden brown. Remove from the oven and cool on a wire rack for 10 to 15 minutes.
A nonstick tart pan with a removable bottom makes it super easy to remove the tart from the pan. Just press up underneath to pop it up and then use a spatula to slide the tart off the nonstick base and onto a serving plate.
FAQ and Valerie’s Tips
Yes! To freeze a whole unbaked onion tart, place it on a baking sheet and freeze it until firm. Then, wrap it with a layer of heavy duty foil and place it in a zippered, freezer-safe plastic storage bag and freeze for up to 1 month. Unwrap and bake from frozen, adding 15 to 20 minutes extra time.
To freeze a baked tart or individual slices, wrap and freeze the completely cooled tart as directed above. To reheat, unwrap and bake the frozen tart in a preheated 350 degree F oven for about 25 minutes, or until heated through.
To reheat an entire refrigerated onion tart, first let it rest on the kitchen counter for about 30 minutes to take the chill off. Meanwhile, preheat your oven to 350 degrees F. Place the tart on a baking sheet, cover it with aluminum foil, and bake for 15 to 20 minutes or until the internal temperature reads 165 degrees F.
You can reheat individual slices in the microwave for 20 second increments until warmed through.
While a tart can be either sweet or savory, a quiche is always savory and typically has a higher ratio of an eggy custard base with cheese. Tarts have a lower ratio of custard and instead, the other ingredients are the star – in this case, caramelized onions. Both are delicious for brunch, lunch, or a light dinner.
What to Serve with Onion Tart
- Light Meal – Serve it with Lemon Parmesan Salad or Butter Lettuce Salad with Grapes and Gorgonzola.
- Substantial Menu -Serve it along with a pasta dish like Meaty Tortellini Skillet or cooked pasta tossed in Easy Tomato Cream Sauce
- Holiday Brunch Menu – Add to any brunch menu with other items like Oven Roasted Breakfast Potatoes, Spinach Mushroom and Feta Crustless Quiche, Cranberry Breakfast Cake, or Maple Pecan Sticky Buns.
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Caramelized Onion Tart
Equipment
- pie weights or dry beans
Ingredients
- 1 unbaked refrigerated pie crust, I used Pillsbury
- 5 bacon slices, not thick-cut, cut into ½-inch pieces
- 1 tablespoon butter
- 2 pounds sweet yellow onions, halved and thinly sliced (2+ good sized onions)
- 1 ¼ teaspoon kosher salt, divided
- 3 large eggs
- ⅔ cup sour cream, or crème fraiche
- 1 tablespoon chopped fresh sage
- 1 tablespoon chopped fresh thyme
- ½ teaspoon freshly ground black pepper
- ⅛ teaspoon ground nutmeg
Instructions
- Preheat oven to 400 degrees F. Remove the pie crust from the refrigerator and let it rest at room temperature while you prepare the bacon and onions.
- Cook the bacon in a saute pan over MEDIUM-HIGH heat, stirring frequently, until crisp. Use a slotted spoon to transfer the bacon to a double layer of paper towels to drain. Leave the bacon drippings in the skillet.
Caramelize the Onions
- Reduce heat to MEDIUM and melt the butter with the bacon drippings in the skillet. Add the onions and ¼ teaspoon salt and cook, stirring frequently, for 5 minutes. Cover and cook for about 8 to 10 minutes, stirring every 2 minutes or so and then covering again, until the onions are soft and golden brown. If they begin to burn, reduce the heat under the skillet, as needed. Uncover and cook for an additional 2 to 3 minutes or until deep golden brown and any liquid in the skillet has evaporated. Remove the skillet from the heat and allow the onions to cool while you parkbake the crust.
Parbake the Crust
- Coat the bottom and sides of a nonstick 9-inch tart pan with a removable bottom with nonstick cooking spray.
- Set the pie crust down, centering it in the prepared tart pan. Press it down across the bottom and up the sides of the pan, pressing it into the grooves of the tart pan. If there is a slight overhang of crust around the top edge of the pan, fold it over (towards the inside of the pan) and then press it flat against the sides. The top of the crust should be flush with the top of the tart pan. Lightly prick the bottom of the crust all over with a fork.
- Line the pie pastry with a large sheet of regular (not heavy duty) aluminum foil. Press the foil down across the bottom and against the edges of the crust, pressing it into the fluted edges of the dough. Fill it with pie weights or dry beans, being sure there is weight against the edges of the crust.
- Place the tart pan on a baking sheet (for easy transport in and out of the oven) and bake for 14 to 16 minutes, or until dry (you can lift the foil and peek at the bottom of the crust). Remove from the oven. Carefully lift the foil and weights out of the crust and set the crust aside.
Prepare the Filling
- In a medium bowl, whisk the eggs with the sour cream (or crème fraiche) until smooth. Add the sage, thyme, remaining 1 teaspoon salt, pepper, and nutmeg and whisk again until well combined. Stir in the bacon and cooled onions. Pour the mixture in the prepared crust.
Bake the Onion Tart
- Bake at 400 degrees F for 25 to 30 minutes or until set in the center and golden brown. Remove from the oven and cool on a wire rack for 10 to 15 minutes. Remove from the tart pan, slice, and serve.
- Delicious served warm or at room temperature.
Notes
Nutrition
Nutrition information is automatically calculated using generic ingredients, and is an estimate not a guarantee. For more accurate results, please refer to the labels on your ingredients at home.
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