This quiche is light on eggs but heavy on cream, so it is incredibly rich—a small piece goes a long way. The flax seeds make the crust very tender and give it a deep flavor and color, while the long-cooked onion and fennel take on a deeper caramel flavor. The dough can be made, and the onion and fennel
browned, up to two days in advance; store both, tightly wrapped, in the refrigerator. The finished dish will keep three days, but the bottom crust will start to get a little soft. So if you are serving for guests, make it the day of.
Ingredients
- 1 cup all-purpose flour, spooned and leveled, plus more for the work surface
- ¼ cup finely ground flax seeds
- Kosher salt and freshly ground black pepper
- ½ cup plus 3 tablespoons cold unsalted butter, cut up, divided
- 1 medium yellow onion, chopped
- 1 small fennel bulb, chopped
- 4 large eggs
- 1 cup heavy cream
- ¾ cup whole milk
- Pinch freshly grated nutmeg
- 3 ounces Gruyère, grated (about ¾ cup)
How to Make It
- Place the flour, flax seeds, and 1 teaspoon of salt in a food processor. Pulse until combined. Add the ½ cup of butter and pulse until the butter is broken into pea-size pieces. Drizzle with 3 tablespoons of ice-cold water and pulse to incorporate. The dough should not form a ball in the machine, but it should hold together when squeezed. If it doesn’t hold together, add up to 1 more tablespoon of water and pulse to incorporate. Transfer the dough to a large piece of plastic wrap. Use the plastic wrap to bring the dough together into a ball; flatten into a disk. Refrigerate until firm, at least 30 minutes or up to two days.
- While the dough is chilling, caramelize the onion and fennel. Melt the remaining 3 tablespoons of butter in a medium skillet over medium heat. Add the onion and fennel. Season with salt and pepper. Cook, stirring occasionally, until deep brown in color, 40 to 45 minutes (reduce the heat to medium low if the onions start to burn). Cool to room temperature.
- Preheat oven to 350°F with the oven rack in the lowest position.
- Remove the dough from the plastic wrap and place onto a liberally floured work surface. With a floured rolling pin, roll the dough to a 15-inch circle. Fit the dough into the bottom and sides of a 9-inch springform pan (the dough won’t come all the way up the sides). Refrigerate until chilled, at least 1 hour.
- Whisk together the eggs in a bowl. Add the browned onion and fennel, cream, milk, nutmeg, 1 teaspoon of salt, and ½ teaspoon of pepper and whisk to combine.
- Sprinkle the Gruyère on the bottom of the chilled crust. Pour the egg mixture on top.
- Place the pan on a rimmed baking sheet. Bake until the filling is firm around the edges and just slightly wobbly in the center, 1 hour to 1 hour 10 minutes.
- Let rest for 10 minutes before releasing the sides of the springform pan and slicing the quiche.
