Ingredients
Tart 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
Filling
- 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
Salad
- 4 cups arugula
Instructions
- Make the tart crust: In the base of a food processor, pulse the chilled butter, shortening, flour, and salt together until the butter and shortening pieces are pea-sized. Alternatively, cut the butter and shortening into the flour by hand with a fork or pastry cutter. Add ice water one tablespoon at a time, pulsing until the dough just begins to come together. Avoid over-mixing. Form the dough into a ball, wrap in plastic wrap, and chill in the refrigerator for 30 minutes.
- Roll and chill the crust: On a lightly floured surface, roll the dough into a ¼-inch thick circle. Press it into a tart pan, trimming away excess dough. Use a fork to puncture the dough several times and chill it for an additional 30 minutes.
- Blind bake the crust: Preheat the oven to 400°F with a rack in the center position. Cover the tart crust with foil and bake for 20 minutes. Remove the foil and bake another 10 minutes until the crust is set and lightly golden.
- Cook the onions: In a large saucepan with a tight-fitting lid over medium heat, melt the butter and olive oil, stirring occasionally. Reduce heat to medium-low and add the yellow onion, leeks, green onions, and shallots. Cover and cook for 10 minutes. Remove the lid and continue cooking, stirring frequently, until the onions turn golden brown, about 30 minutes. Remove from heat and let the mixture cool for 20 minutes.
- Make the filling and bake: In a large bowl, whisk together eggs, crème fraîche, kosher salt, ground nutmeg, black pepper, and fresh chives. Fold in the cooled onion mixture evenly. Pour the filling into the pre-baked tart crust and bake for 25 to 35 minutes until the eggs are set and the crust is golden brown.
- Serve with salad: Just before serving, toss the arugula with olive oil, salt, and freshly cracked pepper to taste. Add the dressed arugula on top of the tart slices and serve immediately.
Notes
- Be careful not to overwork the pastry dough to keep it tender and flaky.
- Chilling the dough before rolling and again after lining the tart pan helps prevent shrinking.
- Cooking the onions slowly and evenly ensures a sweet, rich flavor without burning.
- For a richer flavor, use high-quality unsalted butter and fresh herbs.
- The tart can be enjoyed warm or at room temperature.
- Leftovers can be refrigerated for up to 2 days and gently reheated.
- Prep Time: 45 minutes
- Cook Time: 1 hour 55 minutes
- Category: Tart
- Method: Baking
- Cuisine: French
- Diet: Vegetarian
