Prepared with heavy cream, this Gruyère Leek Quiche boasts an exceptionally tender custard and a flaky all-butter crust. This recipe utilizes a classic French custard ratio of 1 egg to ½ cup heavy cream (there's no skimping here!). To ensure success, we're starting with a prebaked quiche crust (we recommend using this quiche crust recipe) and baking the custard at a low temperature. Proteins (such as eggs) cooked at a low temperature will be more tender and retain more fat and moisture than proteins cooked quickly at a high temperature.For an ideal pairing, serve this quiche with a leafy green salad tossed with a bright and acidic vinaigrette.
¼teaspoonfreshly grated nutmegor freshly grated black pepper
Instructions
Note: This recipe requires a 9-inch prebaked quiche crust that is on the deeper side. You can prepare this quiche using a shallow tart or pie pan, but it will most likely not accommodate the full volume of custard prepared in this recipe. You can reduce the custard (using the ratio of 1 whole egg: ½ cup cream) or leftover custard can be baked in a ramekin (to produce a crustless quiche!) at 325°F (165°C) until just set.
Preheat the oven to 325°F (165°C) with a rack in the center position. Place the prebaked quiche crust on a rimmed sheet pan and set aside.
Sauté the Leeks: In a medium skillet, heat the butter and olive oil over medium-low heat. Once the butter has melted and is lightly bubbling, add the sliced leeks and sprinkle with ½ teaspoon kosher salt. Cook, stirring often, until the leeks are soft and tender, about 10 to 12 minutes. If the pan gets dry and they are beginning to gain color, add a small splash of water as needed. Transfer to a small bowl to cool while you prepare the custard.
Prepare the Custard: In a medium bowl, combine the eggs, heavy cream, Dijon mustard, salt, and nutmeg. Whisk until smooth.
Assemble and Bake: Sprinkle the grated cheese onto the bottom of the prebaked crust. Distribute the sautéed leeks in an even thin layer on top. Pour in the egg custard - it should just about reach the top. Carefully transfer to the oven and bake for 40 to 55 minutes or until lightly golden and the custard is set, but still has the slightest jiggle in the center. Set on a wire rack to cool for 10 to 15 minutes before slicing. Serve warm or at room temperature.
Flavor Variation Ideas:
Make this recipe your own. Swap leeks for other sautéed or roasted vegetables, such as mushrooms, broccoli, asparagus, and more. Add crispy pancetta or bacon (. Experiment with fresh herbs, such as dill, parsley, or fresh thyme. Just keep a similar volume and be sure to cook down (sauté or roast) any fresh vegetables to minimize their water content.
Substitution Notes:
Heavy cream boasts a fat content exceeding 35%, significantly higher than whole milk’s meager 3.5% fat. This difference matters, particularly for egg custards. Opting for whole milk or a milk-cream combo is, of course, possible, but will not deliver the best texture or flavor. [Note: This is a classic French quiche, not a light frittata.] Our goal is to make an authentically classic quiche that is exceptional in taste and texture, making the effort and time invested worthwhile.