Sweet caramelized onions and earthy wild mushrooms are a timeless pairing, and this elegant puff pastry tart lets both ingredients shine. Fresh thyme and a splash of balsamic vinegar add depth to every bite, while prepared puff pastry makes the recipe surprisingly easy to pull together. Serve it warm with a crisp green salad for lunch, pair it with roasted vegetables for dinner or slice it into smaller portions for effortless entertaining.

A mushroom and caramelized onion tart on a cooling rack

Wild Mushroom Puff Pastry Tart With Caramelized Onions

Caramelized onions, wild mushrooms and thyme are layered on flaky puff pastry in this elegant savoury tart that's perfect for lunch, dinner or entertaining.

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Ingredients

½ pkg prepared puff pastry thawed
¼ cup olive oil divided
2 onions thinly sliced
1 red onion thinly sliced
2 tbsp granulated sugar
2 tbsp balsamic vinegar
6 sprigs thyme divided
1 tsp each salt and pepper divided
1 tbsp butter
200 g shiitake or chanterelle mushrooms trimmed
2 green onions finely chopped

Instructions

Arrange oven rack to bottom level then preheat oven to 400°F. Unroll puff pastry; press into fluted 9-10-inch tart pan with removable bottom. Line with foil or parchment paper; fill with dried beans. Bake until golden brown and dry on bottom, about 20 minutes. Remove parchment and weights; let cool in pan on rack.
Caramelized onions: Meanwhile, in a large skillet, heat 1 tbsp of the oil over medium-high heat. Add both onions and cook covered, stirring occasionally until no liquid remains and onions are soft, about 6 minutes.
Stir in sugar, vinegar and 1/4 tsp each of the salt and pepper; cook, stirring until onions are dark golden, 7 to 9 minutes. Stir in 2 thyme sprigs and transfer to a plate.
Wipe skillet and heat remaining 3 tbsp oil and butter over medium-high heat; add chanterelles, 3 thyme sprigs and the remaining 3/4 tsp each salt and pepper and cook, stirring until liquid is absorbed, about 5 minutes.
Spread the onion mixture over the puff pastry and top with mushrooms. Bake until pastry is cooked through, and vegetables are warmed, 10 to 15 minutes. Serve with fresh thyme leaves and green onions.

Keyword caramelized onion tart, Caramelized Onions, mushroom tart, puff pastry recipes, puff pastry tart, savoury tart

Tips From the ELLE Gourmet Editors

Choose your mushrooms: Chanterelles bring a delicate, earthy flavour and are at their best from summer through early fall. When they’re unavailable, shiitake mushrooms make an excellent substitute thanks to their meaty texture and rich umami flavour.
Don’t rush the onions: The secret to deeply flavoured caramelized onions is patience. Allow them to cook until they’re soft and richly golden before adding the balsamic vinegar, which enhances their natural sweetness.
Serve it warm—or at room temperature: This tart is just as delicious served at room temperature, making it an excellent choice for entertaining or packing along for a picnic.