Onion Thyme Tart

This onion thyme tart is a cinch to make: frozen puff pastry, yellow onions, thyme, olive oil, and salt. Bingo. Dinner’s done.

A sheet pan with an onion thyme tart on it, covered with cooked onions, thyme on a puff pastry crust

We have a thing for simplicity. At least when it takes the shape of this stunning, conversation-stopping, five-ingredient (yes, five!) appetizer of knee-wobblingly flaky pastry strewn with sweetly caramelized onions and traces of fresh thyme. That’s not to say you can’t embellish this phenomenon from blogger Amy Pennington, whether with a crumbling of feta or goat or blue cheese, a splash of balsamic, maybe even…well, we’ll let you fill in the blank. Originally published December 5, 2011.Renee Schettler Rossi

Onion Thyme Tart

  • Quick Glance
  • (1)
  • 20 M
  • 1 H, 40 M
  • Makes 1 tart
5/5 - 1 reviews
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Heat the olive oil in a large sauté pan over medium heat. Add the onions and stir continuously until softened, 8 to 10 minutes. Sprinkle in the salt and continue stirring until the onions release their moisture and the pan becomes more and more dry. When this happens, add half of the thyme and reduce the heat to medium low. Cook the onions, stirring occasionally, until caramelized and golden, 30 to 40 minutes or so. (If the onions start to brown, reduce the heat as low as your stove goes.) Remove from the heat and set aside.

Preheat the oven to 350°F (176° C). Adjust the oven rack to the center position.

Unfold the sheet of defrosted puff pastry on a parchment-lined baking sheet. You may wish to run a rolling pin over it a couple times just to even the dough. Scatter the top evenly with the onions.

Bake the tart for 25 to 35 minutes, until the pastry is golden brown and flaky. Remove it from the oven, sprinkle the remaining thyme over the top, and let it cool for 10 minutes before slicing into small squares for serving. (Any leftover tart can be kept at room temperature, lightly covered with parchment. Best to crisp it in an oven or toaster oven prior to nibbling.)

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Recipe Testers' Reviews

I love this recipe (and Amy Pennington’s entire cookbook for that matter!) for its simplicity and visual beauty. The charm of this recipe and the cookbook is in having a pantry stocked with basic ingredients at all times, so you can easily throw together delicious and healthful meals any day of the week.

In terms of the recipe itself, I used seven sprigs of thyme (the more the merrier, in my opinion) and I cooked the onions on medium low for 30, not 40, minutes. When I arranged the puff pastry on the baking sheet, I did not roll it out, and I did not leave a border in terms of the onions touching the sides. This seemed to work very well. The crust puffed up and lightly browned and onions were a nice golden, caramelized color when all was said and done. We served it with a nice pea, feta, and crisped prosciutto salad to round out the meal. This simple recipe was a hit, and I will definitely be making it again very soon, no matter what the season.

Simplicity at its best. Loved the final sweet taste and the crispness of the dough. Even the kids totally loved it and wanted more. A perfect appetizer or snack.


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  1. What’s not to love when puff pastry, caramelized onions and thyme are involved? Add a bit of goat cheese, or feta, a touch of balsamic vinegar, and WOW…deliciousness! I used square puff pastry squares from a local market because I like to have the puffy edges on all four sides–makes it easier to hold ;). I used all the thyme I had, about 8 sprigs but I would have enjoyed more. Loved the tip on adding a bit of balsamic vinegar just at the end of cooking the onions. Definitely an easy appetizer or a side, and sure to be a crowd pleaser. My only reservation on the recipe is that for my tastes, two large onions are not enough to cover a sheet of puff pastry. Knowing how much onions shrink when cooked, I used three, and it was barely enough for my six squares.

  2. Yet another great reason to whip up a batch of homemade puff pastry! I have actually been craving an Onion Tart so this is perfect! Delicious in all of its simplicity!

  3. This simple little recipe is just perfect for throwing together as a light meal during the holiday season. I’m a great fan of shortcuts in my cooking (I’m really quite lazy) and this dish lends itself to any number of them. Onions can be brilliantly caramelized in a slow cooker, giving the cook the chance to cook up a huge amount of them and freeze them in portions for later use. There is some absolutely beautiful frozen butter puff pastry available here in Australia, meaning that it can be kept on hand for use with short notice when people drop in unannounced. And, finally, this tart can be adapted a zillion ways to make it as simple or classy as ones pantry or imagination allows. Doesn’t really get much better, does it?

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