A leek tart is a pastry dish, reminiscent of a quiche, which uses leeks as the primary filling ingredient. Although tarts are often made as sweet desserts, a leek tart is more often created to be part of the main meal, much like a quiche. A type of vegetable similar to a green onion, leeks are often used in savory side dishes.
Normally a puff or tart pastry is used for the crust of a leek tart. The pastry is normally bought pre-made but can be made from scratch. Whether store-bought or homemade, the pastry is rolled out and placed into a tart or quiche pan. The edges may be scored and the center is normally pricked repeatedly to keep the pastry from forming a dome while cooking. The center is also sometimes weighted to help prevent rising.
The pastry portion of the leek tart is usually cooked prior to adding the filling. Once complete, the golden crust can be set aside to cool while the filling ingredients are prepared. The filling is primarily composed of leeks and, usually, a custard. The leeks are first chopped and sautéed in oil, butter, or goose fat before being placed in the cooked crust. The sautéed leeks are sometimes referred to as "leeks confit," basically leeks cooked in fat, on the ingredient lists of certain leek tart recipes.
The custard portion of the leek tart is usually made of eggs, whole milk, and double cream or crème fraîche. Some seasonings are also usually included. Salt and pepper are normally the only additional spices, but other flavorings may include shallots or various cheeses. Goat cheese or Gruyère are the most common cheese choices.
Usually prepared by first whisking or beating the eggs, the custard portion of a leek tart then requires the milk and cream to be combined with the beaten eggs. Spices are added, and the custard can be poured into the crust over the leek mixture. After the entire filling has been included in the crust, the tart is baked until the custard sets.
Some versions of leek tart do not use a custard in their creation. Instead, the sautéed leeks are seasoned with salt and pepper and spooned into the baked crust alone. In these cases, the tart is not cooked, merely sliced and served after the leek filling is in place. Leek tart is often removed from the pan before being served.