This vegan French onion tart recipe is a delightful combination of sweet, savory, and flaky textures, perfect for any occasion. Featuring caramelized onions nestled in a crispy puff pastry, this recipe offers a depth of flavour reminiscent of classic bistro dishes like French onion soup, all while being plant-based. It’s a perfect appetizer or a centerpiece for a cozy dinner party.
Why You’ll Love This French Onion Tart Recipe
This recipe is easy, quick, and versatile. With its flaky tart crust and caramelized onions, it’s a crowd-pleaser for any gathering. Plus, using store-bought puff pastry saves time, making it accessible for beginners.
Ingredients & Substitutions
Puff Pastry Sheet
The puff pastry sheet is the foundation of this recipe, creating the delicious flaky tart crust. Make sure to choose a vegan-friendly version, as some puff pastries may contain butter or other animal-derived ingredients. Store-bought puff pastry saves time and effort, making this recipe both easy and approachable. Let it thaw to room temperature before rolling it out to avoid cracks or tears. Its versatility makes it the perfect base for a variety of savory or sweet dishes.
Yellow Onion
Yellow onions are the star of the show, offering a balance of sweetness and savoriness when caramelized. Their natural sugars break down during cooking, creating a rich, deep flavor that’s essential for the recipe. For a twist, you can substitute with red onions for a slightly milder taste or sweet onions for extra sweetness. Slice them into thin slices for even cooking and to ensure they become perfectly tender in the tart.
Fresh Thyme
Fresh thyme brings an aromatic, earthy element to the dish, enhancing its overall depth of flavor. Its delicate leaves complement the caramelized onions beautifully. If fresh thyme isn’t available, you can use dried thyme, but reduce the amount slightly as dried herbs tend to be more concentrated. Other fresh herbs, like rosemary or oregano, can also be used to add variety.
Extra Virgin Olive Oil
This recipe relies on extra virgin olive oil for its nutty flavor and ability to elevate the richness of the dish. It’s used both as a base for the caramelized onions and to drizzle over the tart for added moisture and flavor. A high-quality olive oil can make a big difference in achieving that perfect balance of savory richness.
Maple Syrup
Maple syrup adds a hint of sweetness that balances the savory onions and thyme. Its natural caramel-like flavor complements the balsamic reduction, creating a harmony of sweet and tangy notes. If maple syrup isn’t available, you can substitute with agave syrup or a pinch of sugar, but the complexity of flavor may differ slightly.
Balsamic Reduction
The balsamic reduction is a key ingredient for adding tangy sweetness and a beautiful deep golden brown glaze to the onions. Its concentrated flavor pairs perfectly with the other ingredients, tying the dish together with a burst of acidity. You can find ready-made balsamic reduction at most stores, or make your own by simmering balsamic vinegar until it thickens.
Salt & Pepper
Seasoning with salt and black pepper is crucial to bring out the flavors of each ingredient. A simple sprinkle ensures the dish has the perfect balance of savory and spice. You can adjust the seasoning to suit your taste, but don’t skip it—these essentials enhance every bite.
These simple ingredients work together to create a great flavor profile, making this tart a standout dish for any occasion. Each element, from the caramelized onions to the flaky tart crust, plays a vital role in achieving a harmonious and satisfying result.
Substitutions:
- Replace maple syrup with honey if not strictly vegan.
- Use a white wine reduction instead of balsamic for a lighter tart.
- Swap thyme with rosemary for a herby twist.
Adding Cheese for Non-Vegan Options
If you’re not vegan or dairy-free, adding cheese can take this tart to the next level, enhancing its richness and adding a creamy, savoury element. You can also check out all my vegan cheese recipes here! Here are a few cheese options that pair beautifully with the flavors of caramelized onions and thyme:
Gruyère Cheese
Gruyère is a classic choice often used in French onion soup. Its nutty, slightly sweet flavor adds incredible depth to the tart. Shred or thinly slice Gruyère and place it directly on top of the onions before covering them with the puff pastry. As the tart bakes, the cheese will melt and create a gooey, flavorful layer.
Cream Cheese
For a creamy and slightly tangy twist, a thin spread of cream cheese on the puff pastry before layering the onions works beautifully. The cream cheese adds richness without overpowering the other flavors, making the tart even more indulgent.
Parmesan Cheese
Grated Parmesan cheese is another excellent option. Its salty, umami-rich flavor complements the caramelized onions perfectly. Sprinkle Parmesan over the onions or mix it with Gruyère for a dynamic cheesy layer.
Goat Cheese
If you enjoy a bit of tang, soft goat cheese is a great choice. Crumble it over the onions for a creamy texture and a distinct flavor that pairs wonderfully with the balsamic reduction.
Blue Cheese
For those who love bold flavors, blue cheese can be added in small amounts. Its strong, sharp taste contrasts beautifully with the sweetness of the onions and maple syrup.
Adding cheese is optional but can elevate this tart from a vegan delight to a decadent indulgence. Experiment with your favorites, or mix and match for a unique flavor combination. Just remember to adjust the salt in the recipe, as many cheeses are naturally salty.
Helpful Tools
- Large Skillet: Perfect for caramelizing onions evenly.
- Baking Sheet: Ensures crisp pastry.
- Pastry Brush: Ideal for applying a vegan egg wash.
- Piece of Parchment Paper: Prevents sticking during baking.
- Sharp Knife: To cut puff pastry into clean, even squares.
How to Make This French Onion Tart Recipe
Prep
- Preheat the oven to 350°F.
- Slice the onion into thin slices for quicker cooking.
- Roll out the puff pastry sheet to an even layer, then cut into 9 squares.
Assembly
- Drizzle olive oil, balsamic reduction, and maple syrup onto parchment-lined spots on the baking sheet.
- Add a sprinkle of thyme, salt, and black pepper for flavor.
- Place an onion slice on each spot, covering it with puff pastry.
- Seal the edges and brush the top with vegan butter.
Baking
- Bake for 15–20 minutes or until the pastry is puffed and golden.
- Flip the tarts gently using a spatula for even cooking.
- Serve warm and enjoy your caramelized onion tart.
Tips & Tricks
Blind Bake the Pastry
For a crispier tart crust, blind bake the puff pastry squares for about 5 minutes. Poke small holes in the center with a fork to prevent puffing, ensuring a solid base for your toppings.
Caramelize Onions Properly
Use medium heat to caramelize onions slowly, achieving a deep golden brown color without burning. Stir occasionally, and if they brown too quickly, lower the heat or add a splash of water to prevent sticking.
Balance Onion-to-Pastry Ratio
Ensure the onion slices cover most of the puff pastry to balance flavors. Adjust the size of the pastry or trim onions as needed for a perfect fit.
Use Fresh Ingredients
Fresh thyme and high-quality olive oil add vibrant flavor and richness. These simple upgrades make a big difference in the final dish.
Seal the Edges Well
Firmly press the puff pastry edges to seal them over the onions. Crimping with a fork ensures the filling stays intact while baking.
By following these tips, you’ll create a beautifully crisp and flavorful batch of caramelized onion tarts!
Serving Suggestions
Pair with a simple green salad, a glass of wine, or a comforting bowl of French onion soup for a complete meal. It’s also a great addition to a dinner table spread.
Storing & Reheating
- Storage: Use plastic wrap or an airtight container to store leftovers in the fridge for up to 3 days.
- Reheating: Warm in the oven at 300°F for 10 minutes to regain crispness.
FAQs
Yes, assemble and refrigerate before baking for up to a day.
Try a homemade tart dough or pie crust.
Blind bake the pastry or use a prepared tart pan with a removable bottom.
Yellow onions are ideal, but red onions or sweet onions add variety.
French Onion Tart Recipe With Balsamic and Thyme
Ingredients
- 1 sheet puff pastry, thawed
- 1 small yellow onion
- 4 sprigs fresh thyme or a few sprinkles of dry thyme
- extra virgin olive oil
- maple syrup
- balsamic reduction
- salt & pepper to taste
Instructions
Prep
- Pre-heat the oven to 350°.
- Cut the onion into thin circular slices. Thinner is better as they will cook faster in the oven.
- If your puff pastry doesn't already come in a rolled out sheet, roll it out into a fairly thin layer. See photos for reference.
- Cut the puff pastry into 9 equal squares. Make sure that the onion slices will be fully covered by the puff pastry and adjust the amount or size if needed.
Assembly
- On a baking sheet lined with parchment paper, drizzle 9 spots with a little olive oil, balsamic reduction, maple syrup and fresh thyme. See photos above for reference, you'll want just enough to fully cover the onion slices.
- Place the onion slice on top of the olive oil mixture and sprinkle with salt and pepper to taste.
- Cover each onion with a square of the puff pastry and press all the edges down to seal them. Brush the tops of the pastry with melted vegan butter if desired.
Baking
- Bake at 350 for 15-20 minutes or until the pastry is golden brown. Flip them over using a spatula, you may have to shimmy the spatula a little to ensure it all stays together. Serve warm and enjoy!
Notes
Nutrition
Conclusion: French Onion Tart Recipe
This vegan French onion tart is the ultimate fusion of elegance and ease. Its great flavor and versatility make it a standout choice for gatherings or a cozy night in. Whether you’re a fan of classic bistro dishes or looking to try something new, this recipe will impress every time.
Yum!! I made these for a family get together as an appetizer and they got gobbled up so quick! Loving your blog and recipes 😊
YAYYYY I’m so happy to hear!!! I’m obsessed with this recipe too and I’m so happy everyone loved it! ☺️
Awesome appy!! So quick and easy to make and was so tasty all my guest loved them too
I’m so happy you loved this recipe! Thank you so much 🙂