Ingredients
Crust
- ½ cup (1 stick) unsalted butter, chilled and cut into small pieces
- ½ cup vegetable shortening
- 2 cups all-purpose flour, plus more for rolling
- ½ teaspoon sea salt
- 5 to 6 tablespoons ice water
Tart & Salad
- 4 tablespoons (1/2 stick) unsalted butter
- 2 tablespoons extra-virgin olive oil, plus more for salad
- 1 large yellow onion, thinly sliced
- 2 leeks, sliced
- 4 green onions, thinly sliced
- 2 shallots, thinly sliced
- 4 large eggs
- ⅓ cup crème fraîche
- ½ teaspoon kosher salt, plus more for salad
- ¼ teaspoon ground nutmeg
- ½ teaspoon freshly cracked black pepper, plus more for salad
- ½ cup minced fresh chives
- 4 cups arugula
Instructions
- Prepare the crust: In a large mixing bowl, combine the chilled unsalted butter and vegetable shortening with 2 cups of all-purpose flour and ½ teaspoon sea salt. Using a pastry cutter or your fingers, blend the fat into the flour until the mixture resembles coarse crumbs. Gradually add 5 to 6 tablespoons of ice water, stirring gently until the dough just comes together. Form the dough into a disk, wrap it in plastic wrap, and chill in the refrigerator for at least 30 minutes.
- Roll out the dough: On a lightly floured surface, roll out the chilled dough into a 12-inch circle. Carefully transfer it to a tart pan, pressing it into the corners and trimming any excess. Chill the tart shell in the refrigerator while you prepare the filling.
- Sauté the onions: In a large skillet, melt 4 tablespoons of unsalted butter with 2 tablespoons of extra-virgin olive oil over medium heat. Add the thinly sliced yellow onion, leeks, green onions, and shallots. Cook gently, stirring frequently, until the onions are very soft and caramelized, about 20-25 minutes. Remove from heat and let cool slightly.
- Preheat the oven: Set your oven to 375°F (190°C) to preheat while you assemble the tart.
- Make the custard filling: In a medium bowl, whisk together the 4 large eggs, ⅓ cup crème fraîche, ½ teaspoon kosher salt, ¼ teaspoon ground nutmeg, and ½ teaspoon freshly cracked black pepper until smooth.
- Assemble the tart: Evenly spread the caramelized onion mixture over the chilled tart shell. Pour the egg and crème fraîche mixture over the onions. Sprinkle the minced fresh chives evenly on top.
- Bake the tart: Place the tart in the preheated oven and bake for 35-40 minutes, or until the custard is set and the crust is golden brown. Remove from the oven and allow it to cool slightly before serving.
- Prepare the arugula salad: In a large bowl, toss 4 cups of fresh arugula with a drizzle of extra-virgin olive oil, a pinch of kosher salt, and freshly cracked black pepper to taste.
- Serve: Slice the tart and serve it warm or at room temperature alongside the fresh arugula salad dressed simply to complement the tart’s rich flavors.
Notes
- Make sure the butter and shortening are very cold for a flaky crust.
- Caramelize the onions slowly over medium to low heat to bring out their natural sweetness and avoid burning.
- Crème fraîche can be substituted with sour cream or heavy cream if unavailable.
- The tart can be prepared a day in advance and reheated gently before serving.
- For added flavor, sprinkle some grated Parmesan cheese on top before baking.
- Prep Time: 45 minutes
- Cook Time: 40 minutes
- Category: Tart
- Method: Baking
- Cuisine: French
