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slice of sweet potato puff pastry pie on a vintage plate

Sweet Potato Puff Pastry Pie

This savory sweet potato puff pastry pie with caramelized balsamic onions and cheese would make a fantastic vegetarian Thanksgiving dish.
Course Pies and Cheesecakes
Cuisine American
Prep Time 30 minutes
Cook Time 50 minutes
Total Time 1 hour 20 minutes
Servings 12
Calories 350kcal
Author Adina


  • 9 oz white or yellow onions 250 g
  • 9 oz red onions 250 g
  • 2 tablespoons extra virgin olive oil
  • ½ teaspoon dried thyme
  • 2 tablespoons sugar
  • 6 tablespoons balsamic vinegar
  • 1.3 oz sweet potatoes 600 g
  • 3/4 cup Gruyere cheese or a vegetarian alternative 150 g (Note 1)
  • 10 oz puff pastry 275 g (Note 2)
  • 2 eggs
  • 1 cup heavy cream about 30% fat, 250 ml
  • fine sea salt and freshly ground black pepper


  • Preheat the oven to 200 degrees Celsius/ 400 degrees Fahrenheit.
  • Cook onions: Peel and slice the onions. Heat the olive oil in a large non-stick pan and saute the onions on medium-low heat until translucent and starting to get soft, about 8 minutes. Add the thyme, sugar, and balsamic vinegar and continue cooking the onions, stirring often, until the onions start to caramelize and are soft. Remove and let cool slightly while you prepare the rest.
  • Prepare sweet potatoes and cheese: Peel and slice the sweet potatoes into thin slices with the help of a mandoline. Set aside. Grate the cheese and set it aside as well.
  • Line a round baking/gratin dish of approximately 26 cm/ 10 inches with the rolled puff pastry.
  • Prepare pastry: Thaw it and roll it according to the packet's instructions if using frozen puff pastry. Place it in the prepared tin. Pierce the pastry with a fork all over.
  • Assemble the pie: Divide the sweet potatoes into three even portions. Arrange one part of the potatoes into the baking dish, sprinkle generously with sea salt and black pepper. Cover with half of the onions and half of the grated cheese. Repeat with the second portions of sweet potatoes and the remaining onions and cheese. End with a layer of sweet potatoes.
  • Whisk the eggs and cream. Season well and pour the mixture into the gratin dish.
  • Bake for 50 minutes or until the sweet potatoes are cooked through. Loosely cover the pie with aluminum foil after about 30 minutes of baking time to prevent the top of the pie from getting too dark. Let the pie rest for about 10 minutes before serving.


  1. Gruyere is a good melting cheese. You can substitute it with another kind of good melting cheese you like. If you want this pie to be vegetarian, make sure to choose a vegetarian type of cheese.
  2. I use already rolled puff pastry found in the refrigerator section of the supermarket (in Germany). You can use homemade puff pastry or frozen puff pastry, which should be thawed and rolled according to the packet's instructions.


Serving: 1slice | Calories: 350kcal | Carbohydrates: 29g | Protein: 8g | Fat: 23g | Saturated Fat: 9g | Polyunsaturated Fat: 13g | Cholesterol: 38mg | Sodium: 272mg | Fiber: 3g | Sugar: 9g