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Golden baked butternut squash tart topped with caramelized onions on puff pastry
Isaac blogger

Savory Butternut Squash Tart with Caramelized Onions

A cozy fall tart made with flaky puff pastry, roasted butternut squash, and slow-caramelized onions. This savory vegetarian tart is simple to prepare and perfect for dinner, entertaining, or holiday gatherings.
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Prep Time 25 minutes
Cook Time 55 minutes
Total Time 1 hour 20 minutes
Servings: 6
Course: Main Course / Appetizer
Cuisine: American (Fall)
Calories:
Ingredients Method Notes

Ingredients
  

  • For the Tart
  • 1 medium butternut squash, peeled, seeded, and cubed
  • 2 large yellow onions, thinly sliced
  • 1 sheet puff pastry, thawed
  • 2 tablespoons olive oil, divided
  • 1 tablespoon unsalted butter
  • 4 ounces goat cheese, feta, or Gruyère
  • 1 teaspoon fresh thyme (or ½ teaspoon dried)
  • Salt and black pepper, to taste
  • 1 large egg, beaten (for egg wash)
  • Optional
  • Balsamic glaze or honey, for serving

Method
 

  1. Before You Begin
  2. Prepare your cookware as needed. Cooking times and results may vary depending on equipment, ingredient size, and oven performance.
  3. Roast the Squash
  4. Preheat oven to 400°F (200°C). Toss squash with 1 tablespoon olive oil, thyme, salt, and pepper. Spread on a baking sheet and roast 20–25 minutes, until fork-tender and lightly browned.
  5. Caramelize the Onions
  6. Heat butter and remaining olive oil in a skillet over medium-low heat. Add onions with a pinch of salt and cook 30–40 minutes, stirring occasionally, until deep golden and caramelized.
  7. Prepare the Pastry
  8. Reduce oven temperature to 375°F (190°C). Place puff pastry on a parchment-lined baking sheet.
  9. Assemble the Tart
  10. Spread caramelized onions over the pastry, leaving a border. Top with roasted squash and cheese. Fold edges inward and brush with egg wash.
  11. Bake
  12. Bake until pastry is puffed and lightly golden. Remove from oven and allow to rest briefly.
  13. Serve
  14. Slice and serve warm or at room temperature. Drizzle with balsamic glaze or honey if desired.

Notes

  • Roast squash until fork-tender and lightly browned; avoid overcrowding to prevent steaming.
  • Caramelize onions slowly over medium-low heat to prevent burning.
  • Keep puff pastry cold before baking for the flakiest texture.
  • Bake until pastry is golden and filling is heated through; rest 5 minutes before slicing.
  • Refrigerate leftovers within 2 hours in an airtight container for up to 3 days.
  • Reheat in a 325–350°F (165–175°C) oven until heated through and crisp.
  • Avoid reheating more than once and discard if smell, texture, or appearance changes.