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Apple and Caramelized Onion Tart

Recipe for a Apple and Caramelized Onion Tart! A flaky pie crust is filled with a caramelized onion gruyere mixture and topped with sliced apples.
Course Side Dish
Cuisine N/A
Keyword apple, apple pie, caramelized onion, onion, pie, tart
Prep Time 20 minutes
Cook Time 1 hour 30 minutes
Resting Time: 2 hours
Total Time 3 hours 50 minutes
Servings 1 (9 inch) Tart


Pie Crust:

  • 1 1/4 cups all-purpose flour
  • 1 tablespoon granulated sugar
  • 1/4 teaspoon salt
  • 8 tablespoons unsalted butter chilled and diced
  • 2 1/2 tablespoons cold water
  • 1/2 tablespoon apple cider vinegar
  • Butter for greasing pie pans


  • 2 apples cored and thinly sliced
  • 1/4 teaspoon salt
  • 2 tablespoons granulated sugar


  • 2 tablespoons unsalted butter divided
  • 1 tablespoon olive oil
  • 1 teaspoon fresh sage leaves thinly sliced
  • 3 large onions cut in half and thinly sliced
  • 2 eggs
  • 1/4 cup heavy cream
  • 3/4 cup shredded gruyere


To make the pie crust:

  • In a large bowl, mix together the flour, sugar, and salt. Cut in the chilled butter using a dough blender, forks, or your fingers until the texture becomes coarse and no pieces are larger than the size of a pea. Mix in the water and vinegar just until a smooth dough forms.
  • Flatten the dough into a disc and wrap in plastic. Refrigerate for at least 30 minutes.
  • Grease 6 (4.75 inch) tart pans or 1 large tart pan (9 inch) with butter. On a lightly floured surface, roll the dough into a thin circle large enough to cover the bottoms and sides of the 9 inch pan or divide among the 6 (4.75 inch) dishes.
  • Transfer to the pans, pressing to cover the bottom and slightly overlap the sides. Prick the bottoms a few times with a fork. Place in the refrigerator for another 30 minutes.
  • Preheat oven to 400˚F. Cover each pie crust-lined pan lightly with parchment and fill with ceramic pie weights or uncooked rice. Bake for 10 minutes. Remove from oven and remove the parchment.

To make the apples:

  • Place the thinly sliced apples in a colander over a bowl or in the sink. Sprinkle with salt and sugar, then toss to coat. Allow to sit for an hour while preparing the remaining ingredients.

To make the caramelized onion base:

  • In a large pot, melt together 2 tablespoons butter and olive oil over medium heat. Add the sage and cook for about a minute to crisp. Mix in the onions and salt. Cook for a minute, then reduce heat to medium low. Cover and cook, stirring occasionally, until golden and caramelized, 30-45 minutes. Transfer the onions to a bowl and allow to cool to room temperature.
  • Preheat oven to 425˚F. Mix the eggs and heavy cream into the cooled onions. Divide among the partially baked pie dishes. Top evenly with cheese.
  • Arrange a few apple slices flat over the filling around the edge with the peel side facing the crust. This will create a base for layering the remaining apple slices.
  • Starting along the edge, layer the apple slices in a circular pattern, alternating the direction if desired and if room is available using the larger tart pan (there wasn't enough space in the 4 inch tart pans). Brush the tops with melted butter and bake in the 425˚F oven until the filling is set and the crust is golden, about 30 minutes (closer to 40-45 minutes for a 9 inch tart). If the edges of the apples are starting to burn, cover lightly with foil and reduce heat to 375˚F.
  • Serve warm or at room temperature.