Caramelized Onion and Gruyère Tart

A savory tart featuring deeply caramelized onions and nutty Gruyère cheese baked on buttery puff pastry—a taste reminiscent of French onion soup in tart form. Don’t Go Bacon My HeartAllrecipes+8Spicy Southern Kitchen+8Lost in Food+8Whisked Away KitchenSpicy Southern Kitchen+4Lost in Food+4Lost in Food+4Lost in FoodOh My Veggies+6holisticfoodie.com+6Kendall-Jackson Wines+6

Why You’ll Love This Recipe

• Soul-warming and comforting, sophisticated yet simple.
• Make-ahead components—onions or pastry can be prepped earlier.
• Elegant enough for gatherings, casual enough for weeknights. holisticfoodie.com

ingredients

(Tip: You can find the complete list of ingredients and their measurements in the recipe card below.)

• Puff pastry sheet (store-bought all-butter recommended)
• Sweet onions, thinly sliced
• Butter and olive oil
• Garlic, minced
• Gruyère cheese, grated
• Parmesan cheese (optional)
• Thyme (fresh or dried), salt, pepper
• Optional: a splash of wine (e.g., Chardonnay), brown sugar

directions

1. Cook onions slowly in butter and oil until soft, golden, deeply caramelized (30–45 min); add garlic toward the end. Craving Something HealthyWhole Food Bellies+3Kendall-Jackson Wines+3Brooklyn Supper+3RedditBeyond The Chicken Coop
2. Unroll pastry onto baking sheet; optionally brush edges with mustard or milk for browning. Kendall-Jackson WinesBon Appétit
3. Spread onions evenly over pastry; top with Gruyère—and Parmesan if desired.
4. Bake until pastry is crisp and cheese melted (approx. 15–20 minutes at ~200 °C/400 °F).
5. Let cool slightly before slicing and serving.

Servings and timing

• Servings: About 6 portions.
• Prep Time: ~15 minutes (plus onion caramelizing time).
• Cook Time: ~15–20 minutes pastry bake.
• Total Time: ~60–70 minutes including onion cooking. Kendall-Jackson Wines+2holisticfoodie.com+2

Variations

• Substitute goat cheese or mix in a layer of fig jam for sweetness. The Guardian+5The Cozy Plum+5The Kitchn+5
• Add sliced mushrooms or fresh herbs like sage or tarragon for complexity. Brown Eyed BakerNot Quite NigellaBrooklyn Supper

storage/reheating

• Store in refrigerator for up to 2–3 days.
• Reheat in a low oven until warmed and crisp.

FAQs

Can I caramelize onions ahead of time?

Yes—onions can be made up to a week in advance and refrigerated. Bon Appétit

What pastry works best?

All-butter puff pastry offers the flakiest, most buttery result; store-bought is perfectly fine.

Can I use different cheese?

Gruyère is ideal, but Swiss, Emmental, Jarlsberg, or cheddar can work. Kendall-Jackson Wines+3Brooklyn Supper+3Brown Eyed Baker+3Craving Something Healthy

How do I prevent soggy pastry?

Let onions cool slightly before layering to allow juices to reduce.

Can I add mustard to the base?

Yes—a thin layer of mustard adds depth and balances sweetness. Bon Appétit

Can I make mini tarts?

Absolutely—cut pastry into rounds or squares, layer filling, and bake for bite-size versions. Whole Food Bellies

What’s a good side pairing?

A crisp green salad or charcuterie makes an elegant match.

How to store leftovers?

Refrigerate up to 2–3 days; reheat gently to maintain crispness.

Can I omit garlic?

Yes—only onions and cheese still yield a flavorful result.

Conclusion

This caramelized onion and Gruyère tart is a refined yet comforting dish—perfect as an elegant appetizer or a light entrée alongside salad. Its rich flavors and simple prep make it a kitchen staple.

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