French · Dinner

Onion and Pancetta Tart

A rich, savory tart featuring slowly caramelized onions, crispy-edged pancetta, and nutty Gruyère cheese in a buttery walnut pastry crust. With just enough creamy custard to bind the filling, this elegant tart is perfect for brunch, entertaining, or a light dinner.

Onion and Pancetta Tart
Prep25 min Cook1 h 35 min Serves 12 Servingsmall slices

Ingredients

  • All-purpose flour ≈ 小麦粉 for dusting
  • ⅔ recipe Walnut Dough くるみ see note
  • Extra-virgin olive oil オリーブオイル for cooking
  • 3 oz pancetta chopped
  • 3 cup thinly sliced yellow onion 玉ねぎ about 1 large onion
  • to taste Kosher salt and freshly ground black pepper ≈ 粗塩・黒こしょう(粉)
  • 1 large egg yolk 卵
  • ½ cup heavy cream or crème fraîche 生クリーム
  • 2 oz Gruyère cheese チーズ approximately 1/2 cup, shredded

Steps

  1. Preheat the oven to 400°F (205°C).

  2. On a lightly floured surface, roll the walnut dough into a 13-inch circle. Transfer to a 10-inch tart pan with a removable bottom. Gently press the dough into the corners and sides, forming an even rim.

    Walnut くるみ

  3. Line the pastry with parchment paper or foil and fill with pie weights or dried beans. Bake for approximately 10 minutes, until the dough is set and the edges are lightly browned.

  4. Reduce the oven temperature to 325°F (165°C). Remove the parchment and weights, then return the tart shell to the oven for another 20 minutes, until the bottom is dry and lightly golden. Allow to cool slightly.

  5. While the crust bakes, heat a small amount of olive oil in a large skillet over medium-high heat. Add the pancetta. Once it begins to sizzle, reduce the heat and cook for approximately 7 minutes, until the fat renders and the pancetta begins to brown without becoming crispy.

    Olive oil オリーブオイル

  6. Add the sliced onions and season generously with salt and pepper. Cook gently for approximately 30 minutes, stirring frequently, until the onions are very soft, fragrant, and golden brown. Allow to cool to room temperature.

    Onion 玉ねぎ Salt 塩 Black pepper こしょう

  7. In a mixing bowl, whisk together the egg yolk and heavy cream or crème fraîche. Season lightly with salt and pepper.

    Egg yolk 卵黄 Heavy cream 生クリーム Salt 塩 Black pepper こしょう

  8. Fold the shredded Gruyère and cooled onion mixture into the custard. Pour into the prepared tart shell and smooth the surface.

    Onion 玉ねぎ

  9. Bake at 325°F (165°C) for approximately 20 minutes, until the filling is just set.

  10. Allow the tart to cool until warm before slicing and serving.

Notes

Walnut Dough: The original cookbook calls for its Pecan Dough recipe, substituting walnuts for pecans. Only two-thirds of that dough is needed. The pastry recipe itself isn't included in your photos.

Make Ahead: This tart reheats beautifully, making it an excellent choice for entertaining. Prepare it a day ahead, refrigerate, and gently reheat before serving.

Serving Suggestion: Pair with a lightly dressed green salad or fresh seasonal vegetables for an elegant brunch or lunch.