Upside-Down Onion Tarts

I love breaking the mold in the kitchen, and these Upside-Down Onion Tarts are the perfect example. The crispy, golden pastry crust envelops a rich filling made with caramelized onions, sun-dried tomatoes, and olives. These little savory bundles are great for an unconventional aperitif, especially during the holiday season, adding a twist to classic recipes.

Puff pastry is always a great choice when you’re looking for a quick and easy appetizer, as you can customize it with whatever ingredients you prefer. These Upside-Down Onion Tarts are a creative twist, using just a few basic ingredients and simply flipping the pastry. The result is not only visually appealing, but when you taste it, you’ll enjoy the layers that make up the rich filling. The first step in creating the seasoning at the base of the tart, drizzling olive oil, balsamic vinegar, oregano, chilli flakes, salt, and black pepper, is crucial, as it enhances the flavor and helps the caramelize the onions.

These Upside-down Onion Tarts are inspired by the classic Tarte Tatin, a French baked dessert with a golden pastry base and caramelized fruit topping. A great addition is cheese, such as goat cheese, feta or Parmesan, to create a grilled layer on top of the onions and add extra richness.

Before flipping and storing the Upside-Down Onion Tarts, make sure they are completely cool to prevent them from becoming soggy. You can keep them in an airtight container in the fridge for up to 2-3 days, or in the freezer for up to 1 month. I suggest reheating them to enjoy them warm, and for this, I place them in the oven for 10-15 minutes to restore the crispiness of the pastry.

Ingredients for savory tarts

• Onion: when caramelized, they develop a sweet and savory flavor, becoming tender and complementing the crispiness of the puff pastry. When you flip the tart, the glossy topping makes the dish mouthwatering and visually appealing. I use red onions, but any type of onion you prefer is fine, as the only important thing is to cut the slices thin enough to ensure even cooking.

• Sun-dried tomatoes: they have a natural sweetness and tangy flavor that complement the caramelized onions. Moreover, sun-dried tomatoes provide a chewy texture that creates a pleasant contrast with the soft onions and crispy puff pastry. Finally, their vibrant red color adds visual appeal to the Upside-Down Onion Tarts.

• Black olives: their savory flavor enhances the overall umami profile of the dish, and their firm texture creates a delightful contrast. Additionally, black olives add a dark, glossy touch that contrasts beautifully the golden puff pastry and caramelized onions.

• Oregano: this herb provides a slight peppery taste, complementing the rich ingredients such as sun-dried tomatoes and black olives. Moreover, oregano reflects Mediterranean cuisine, adding an authentic flavor to the Upside-Down Onion Tarts. Finally, this herb brings a touch of vibrant green color, making the recipe even more visually appealing.

• Chilli flakes: their warmth contributes to the depth and complexity of the flavor. The spiciness balances the richness of the other ingredients, and when baked, they provide a warming aroma. In addition, chilli flakes add a red touch to the dish, enhancing the overall presentation.

• Balsamic vinegar: the tangy-sweet and sour flavor complements the sweetness of the onions and the richness of the puff pastry. Balsamic vinegar contains natural sugars that aid in the caramelization process, giving the onions a glossy top layer. Finally, this ingredient is a classic in Mediterranean cuisine, adding an authentic touch to the Upside-Down Onion Tarts.

Find the complete recipe with measurements below.

How to prepare a creative aperitif

Drizzle oil and balsamic vinegar around the baking sheet to make 8 little circles.  Sprinkle some oregano, chilli flakes, salt and pepper. Ten top with an onion slice.

Put a sun-dried tomatoes and olive on top of every onion slice and finish by covering with a square of puff pastry. Press the edges and brush some egg yolk over the pastry.

Bake for about 15 minutes or until golden at 190°C.

My tips for rich little tarts

• Caramelize the onions in a pan before adding them to the Upside-Down Onion Tarts, in order to add extra richness and making them softer.

• Keep the puff pastry in the fridge until you start to assemble the tarts.

• Avoid adding too many ingredients under the puff pastry, otherwise it will be harder to seal the edges.

• Once the tarts are fully cooked, drizzle extra balsamic vinegar and sprinkle some some herbs on top.

Did you try this recipe? Don’t forget to share it with me tagging @nutritiouslysofia on Instagram!

Upside-Down Onion Tarts

Course: Appetizers, Snacks, MainCuisine: vegan, vegetarian

Servings

6

servings

Prep time

10

minutes

Cooking time

18

minutes

Ingredients

• Puff pastry 1

• Onions

• Sun-dried tomatoes

• Black olives

• Olive oil

• Balsamic vinegar

• Oregano

• Chilli flakes

• Salt

• Black pepper

• Egg yolk

Directions

• Drizzle oil and balsamic vinegar around the baking sheet to make 8 little circles.  Sprinkle some oregano, chilli flakes, salt and pepper. Ten top with an onion slice.
• Put a sun-dried tomatoes and olive on top of every onion slice and finish by covering with a square of puff pastry. Press the edges and brush some egg yolk over the pastry.
• Bake for about 15 minutes or until golden at 190°C.

Notes

• Caramelize the onions in a pan before adding them to the Upside-Down Onion Tarts, in order to add extra richness and making them softer.
• Keep the puff pastry in the fridge until you start to assemble the tarts.
• Avoid adding too many ingredients under the puff pastry, otherwise it will be harder to seal the edges.
• Once the tarts are fully cooked, drizzle extra balsamic vinegar and sprinkle some some herbs on top.