by 
This Onion Tart has a flaky crust topped with cooked sweet onions and fresh thyme. Serve as an elegant appetizer!
Puff pastry tart
I recently took a three-day baking class from King Arthur Baking School. It was entirely focused on laminated dough or puff pastry. We made four different types of puff pastry, and this onion tart is inspired by a recipe we made during the workshop.
The base of the tart is puff pastry. In the workshop, we used a blitz puff pastry, also called easy puff pastry. You can make this with store-bought puff pastry, too!
The end result is a delicious tart! It makes a perfect appetizer, but we ate the leftovers for lunch, and we even nibbled on a piece for breakfast! We just couldn't resist!
You'll also want to check out this Tomato Tart!
Key ingredients for onion tart
This section reviews the best ingredients and substitutions for this recipe. For an exact list of ingredients and quantities, check the recipe card below.
- Puff pastry - Use homemade puff pastry or store-bought puff pastry. My easy puff pastry works perfectly in this recipe.
- Onion - I like to use a sweet onion. Try a Walla Walla sweet onion or a Vidalia sweet onion.
- Greek Yogurt - Use plain Greek yogurt. This adds a bit of tang to the tart. You could also use Cream Fraiche (this is what we used in the workshop), sour cream, or a very soft, whipped cream cheese or homemade Boursin.
- Fresh Herbs - I used fresh thyme, but rosemary is also a delicious option.
Making the onion tart
In this section, I share step-by-step photos, cooking methods, techniques, and a general overview. For detailed instructions, temperatures, and timing, check the printable recipe card below.
- Slice onions from pole to pole (or end to end), creating long strips.
- Sauté onions in a hot pan with a bit of olive oil until they are soft and slightly translucent. Remove onions from the pan and allow to cool slightly.
- Roll out your puff pastry into a 10x10-inch square. If using store-bought puff pastry, it usually comes in a rectangle. No need to roll it out.
- Trim ¼ - ½ inch of each side. Save these pieces!
- Place puff pastry on a baking sheet lined with parchment paper.
- Brush a thin strip of egg wash around the perimeter of the puff pastry.
- Place the trimmed pieces on top of the egg wash. This becomes the sides of the tart.
- Brush the top of the pastry with egg wash.
- Spread Greek yogurt over the inside of the tart.
- Add onions.
- Top with grated Parmesan cheese
- Sprinkle with fresh herbs and a bit of salt and pepper.
- Bake in preheated 400°F oven for 20-25 minutes, until pastry is fully cooked.
- Allow tart to cool for at least 10 minutes before slicing and serving.
Recipe tips
- Use a sharp knife or pizza cutter wheel to slice the edges of the puff pastry.
- Avoid getting the egg wash on the sides of the tart. This will seal the puff pastry, and it may not rise into the flaky layers.
- Place the cut ends of the pastry with the rough, or uneven side towards the inside of the pastry. This will give you nice, clean lines on the outside of the tart.
- Allow the tart to cool slightly before slicing
- Serve warm or at room temperature
- Refrigerate leftovers and use within 3-4 days
Recipe Faqs
While this tart is best the same day it is made, you can prepare parts of it ahead of time.
If making your own puff pastry, make it 1-2 days ahead of time.
Cook the onions one day ahead of time.
Leftovers are still delicious and can be stored in the refrigerator for 3-4 days.
Store any leftovers in the refrigerator for 3-4 days.
More delicious appetizers!
If you make this recipe, I’d love to hear about it! Leave a comment below and snap a picture and tag me on Instagram @beyondthechickencoop
Check out all my delicious appetizers!
Onion Tart
Equipment
- Chef Knife
- Cookie Sheet
- Parchment paper
- Basting Brush
Ingredients
- 1 sweet onion
- 1 tablespoon olive oil
- 1 sheet puff pastry (or ½ batch easy puff pastry)
- 1 egg
- 1 tablespoon water
- ¼ cup Greek yogurt (plain)
- 2 tablespoons Parmesan (freshly grated)
- 1 teaspoon fresh thyme
- salt
- pepper
Instructions
- Preheat oven to 400°F
- Saute onions in a hot pan with a bit of olive oil, until they are soft and slightly translucent. Remove onions from pan and allow to cool slightly.1 sweet onion, 1 tablespoon olive oil
- Roll out your puff pastry into a 10x10 inch square. If using store-bought puff pastry, roll it usually comes in a rectangle. No need to roll it out.1 sheet puff pastry
- Trim ¼ - ½ inch of each side. Save these pieces!
- Place puff pastry on a baking sheet lined with parchment paper.
- Make egg wash by mixing egg adn water together. Brush a thin strip of egg wash around the perimeter of the puff pastry.1 egg, 1 tablespoon water
- Place the trimmed pieces on top of the egg wash. This becomes the sides of the tart.
- Spread Greek yogurt over the inside of the tart.¼ cup Greek yogurt
- Add onions.
- Top with grated parmesan cheese2 tablespoons Parmesan
- Sprinkle with fresh herbs and a bit of salt and pepper.1 teaspoon fresh thyme, salt, pepper
- Brush top of pastry with egg wash.
- Bake in preheated 400°F oven for 20-25 minutes, until pastry is fully cooked.
- Allow tart to cool for at least 10 minutes before slicing and serving.
Notes
- Use a sharp knife or pizza cutter wheel to slice the edges of the puff pastry.
- Avoid getting the egg wash on the sides of the tart. This will seal the puff pastry and it may not rise into the flaky layers.
- Place the cut ends of the pastry with the rough, or uneven side towards the inside of the pastry. This will give you nice clean lines on the outside of the tart.
- Allow the tart to cool slightly before slicing
- Serve warm or at room temperature
- Refrigerate leftovers and use within 3-4 days
Nutritional Disclaimer:
Nutritional information is provided as a courtesy and should only be construed as an estimate rather than a guarantee. To obtain the most precise nutritional information in a provided recipe, you should calculate the nutritional information with the exact ingredients you are using when preparing the recipe using your preferred nutrition calculator.
cathy nigro says
Your terrine looks amazing I will be serving it this evening thanks for sharing
Kathy says
Thanks so much! I hope you enjoy it! 🙂
Lily says
Wonderful recipe also useful for left over roasted veges
Kathy says
Thanks so much! Glad you enjoyed it! 🙂
Linda says
Delicious
Kathy says
Thanks so much! I'm so glad you enjoyed it! 🙂
Dan H says
Looks like you have a typo on your recipe... Step 1: preheat the oven to 4000°F?
Kathy says
Oops...400°F...not 4000 🙂
Sylvia says
I have made a similar recipe with a little twist. I thinly slice an apple and place slices on pastry before adding the carmelized onions, then add a sharp cheddar cheese, grated, on top of the tart, then bake as per usual. Yummy!! SS
Kathy says
That sounds like a delicious twist! I'll have to give that a try! 🙂
Ana says
Which type of apple
JulieM says
Making this today and wondered about adding apples - thanks for the confirmation!
Harriet says
Thanks for this recipe. Looks yummy.
I have also used this puff pastry adding asparagus, gruyere cheese and bacon. However, instead of topping the sides of the pastry with the cut pieces, you simply score a line 1 inch from the edge all around the pastry which also makes a lovely raised edge.
Kathy says
Sounds delicious and I like the scoring too!