Name: Sweet Onion and Parmesan Puff Pastry Tart Recipe
Prep time: 10 min
Cook time: 35 min
Total time: 45 min
Cuisine: American
Ingredients: 1 sweet onion; 1 sheet puff pastry (or ½ batch easy puff pastry); ¼ cup Greek yogurt (plain); 2 tablespoons Parmesan (freshly grated); 1 egg; 1 tablespoon olive oil; 1 teaspoon fresh thyme; Salt; Pepper; 1 tablespoon water

Jump to Recipe· 4.2 from 34 reviews

If you’re craving a dish that is as stunning to look at as it is irresistible to taste, then you absolutely must try this Sweet Onion and Parmesan Puff Pastry Tart Recipe. It combines the buttery flakiness of puff pastry with the sweet caramelized notes of fresh onions, all elevated by a generous sprinkle of tangy Parmesan and fragrant thyme. This tart is a delightful balance of savory and creamy that feels special enough for a weekend treat yet simple enough for any weekday gathering. Trust me, once you dive into this recipe, it will quickly become a beloved staple in your culinary rotation.

Ingredients You’ll Need

A white pan filled with sliced cooked onions, showing about two layers of thinly sliced onion pieces, lightly browned and caramelized on the edges, with some pieces more golden and crispy near the center. The onions have a soft texture and a mix of pale yellow and light brown color. The pan sits on a white marbled surface. photo taken with an iphone --ar 4:5 --v 7

The magic of this recipe lies in its straightforward, wholesome ingredients. Each component plays a crucial role in building the tart’s layers of flavor and texture — from the sweetness of the onion to the richness of the Parmesan and the delicate puff pastry that brings it all together.

Sweet onion: The star ingredient, offering natural sweetness and softness once sautéed.
Olive oil: Just enough to tenderly cook the onions without overpowering their delicate flavor.
Puff pastry sheet: This flaky, buttery base provides irresistible texture and a golden crust.
Egg: Used in the egg wash to give the pastry a glossy, appetizing finish.
Water: Mixed with egg to create the perfect glaze for the puff pastry edges.
Greek yogurt (plain): Adds a creamy tang that contrasts beautifully with the sweet onions.
Parmesan cheese (freshly grated): Brings a nutty, savory punch that enhances every bite.
Fresh thyme: A fragrant herb that adds complexity and depth.
Salt and pepper: Essential seasonings to balance and brighten the flavors.

How to Make Sweet Onion and Parmesan Puff Pastry Tart Recipe

Step 1: Sauté the Sweet Onions

Start by heating a tablespoon of olive oil in a pan over medium heat. Add your thinly sliced sweet onion and cook gently until they become soft and slightly translucent. This step is all about coaxing out the onion’s natural sugars to develop that signature sweetness, so avoid rushing it. Once tender, remove the onions from heat and allow them to cool just a little while you prepare the base.

Step 2: Prepare the Puff Pastry

Roll out your puff pastry into a neat 10-inch square on a parchment-lined baking sheet. If you’re using store-bought pastry, it typically comes pre-rolled, but feel free to shape it a bit to fit. Trim about a quarter to half an inch from each side, saving those edges for later. This rim will act as a lovely raised border for your tart, giving it structure and that classic tart look.

Step 3: Egg Wash and Border Formation

Mix the egg with water to create a smooth egg wash. Brush a thin line of this mixture along the edge of your prepared puff pastry square. Then, take the trimmed pastry strips and carefully press them onto the brushed border. This step helps to form a raised edge that will hold in the topping, and the egg wash acts as a glue and gives a golden finish when baked.

Step 4: Layer the Toppings

Spread a generous quarter cup of plain Greek yogurt inside the bordered square. This creamy base will add a subtle tang and moisture, contrasting with the flaky crust and sweet onions. Next, scatter the cooled sautéed onions evenly over the yogurt. Follow up with two tablespoons of freshly grated Parmesan cheese for that salty, savory lift.

Step 5: Season and Bake

Sprinkle the tart with fresh thyme leaves, a pinch of salt, and freshly ground black pepper. Brush the entire puff pastry surface, including the border, with the egg wash for a fabulous golden glaze. Pop the tart into your preheated 400°F oven and bake for 20 to 25 minutes, or until the pastry is risen and beautifully browned. Allow it to cool for at least 10 minutes before slicing to let the flavors meld and the filling set gently.

How to Serve Sweet Onion and Parmesan Puff Pastry Tart Recipe

The image shows a golden-brown puff pastry square with visible layers of flaky crust. On top, there are thin, soft slices of light brown caramelized onions arranged in a swirling pattern, sprinkled with small green herb leaves. The pastry sits on a white parchment paper, which lies on a white marbled surface. In the background, there is a blurred wooden cutting board with fresh green herbs on it. The scene feels warm and rustic, with soft, natural lighting. Photo taken with an iphone --ar 4:5 --v 7

Garnishes

Adding a touch of fresh herbs right before serving can really brighten this tart. Try scattering a few thyme leaves, fresh chives, or even a handful of arugula for a lovely contrast in texture and freshness. A drizzle of quality olive oil or a tiny sprinkle of flaky sea salt can make every bite feel extra special.

Side Dishes

This tart pairs wonderfully with simple, crisp salads that can balance its richness. A light mixed greens salad with a lemon vinaigrette or a vinegary slaw would be perfect companions. For a heartier meal, serve alongside roasted root vegetables or a bowl of warm soup to create a comforting and satisfying spread.

Creative Ways to Present

For a stunning appetizer display, cut the tart into smaller squares or strips and arrange on a wooden board with complementary cheeses and nuts. You can also customize this Sweet Onion and Parmesan Puff Pastry Tart Recipe by adding roasted garlic, caramelized shallots, or a sprinkle of crushed red pepper for subtle heat. The versatility makes it ideal for gatherings or even elegant brunches.

Make Ahead and Storage

Storing Leftovers

If you happen to have any leftovers, they store well in an airtight container in the refrigerator for up to 3 days. To keep the pastry from becoming soggy, let it cool completely before storing and try to reheat it gently to retain that crispness.

Freezing

While this tart is best enjoyed fresh, you can freeze it before baking. Assemble the tart, then cover tightly and freeze for up to one month. Thaw it overnight in the refrigerator and bake as directed, adding a few extra minutes to the cooking time if needed to ensure the pastry puffs up beautifully.

Reheating

The trick to reheating without sacrificing texture is to warm the tart in the oven at 350°F for about 10 minutes. Avoid microwaving, as it tends to make puff pastry soggy. The oven will revitalize that crisp, flaky crust and warm the toppings just right.

FAQs

Can I use other types of onions for this tart?

Absolutely! While sweet onions are preferred for their natural sugar content and mildness, you can experiment with yellow or even red onions. Just remember they may yield a slightly stronger, more pungent flavor.

Is there a vegetarian or vegan alternative for this recipe?

Yes! This recipe is vegetarian as is, but for a vegan twist, substitute the puff pastry with a vegan-friendly version, replace the egg wash with a plant-based milk like almond milk, and swap Greek yogurt and Parmesan for vegan alternatives such as cashew cream and nutritional yeast.

Can I make this tart gluten-free?

To make it gluten-free, look for gluten-free puff pastry in stores or try a homemade gluten-free dough. Keep in mind that texture might differ, but the flavors will remain just as delightful.

What can I add to the tart for extra flavor?

Feel free to add caramelized garlic, sun-dried tomatoes, or even a sprinkle of chili flakes. Fresh herbs like rosemary or sage also add fantastic aromatic notes that complement the sweet onions and Parmesan well.

Is this tart suitable for a brunch menu?

Definitely! This puff pastry tart is light yet flavorful, making it a perfect centerpiece for a brunch spread. Pair with fresh fruit, yogurts, and some crisp mimosas for a memorable meal.

Final Thoughts

I cannot recommend this Sweet Onion and Parmesan Puff Pastry Tart Recipe enough—it’s one of those rare finds that feels indulgent but comes together with minimal fuss. Whether you’re serving it for guests or indulging in a personal treat, its mix of buttery pastry, sweet onions, and savory cheese will win your heart every time. So go ahead, gather these ingredients and experience it yourself—you’ll see why this tart deserves a spot in your favorite recipe book.