Any cuisine that celebrates leeks among its homegrown vegetables is sure to offer a version of leek pie. From Greece to Indonesia, from the U.S. to Wales, leek pies are served up hot or cold, as main dishes paired with salad and bread, or as a light lunch eaten cold from the refrigerator. Some leek pies nestle in a rich, buttery crust, while others enjoy the luxury of sleeping late on a bed of puff pastry or on a faux crust formed by eggs' marriage to cream and cooked to the consistency of a Spanish omelet or tortilla.
Before creating a leek pie, it’s important to understand that queen among onions is the leek. The first time a cook meets a leek, she or he will no doubt try to slice and use the greens just as scallion greens are used. It’s true that a leek looks like a scallion on steroids, but the rubbery green leaves are best left for the stew pot and not the pie.
The second time a cook meets a leek, she or he knows enough to trim off the greens, although the best technique for doing so might be a mystery. With a little more experience, though, the cook will discover that peeling the fibrous, tough leaves back and trimming them with a sharp knife frees up the sweet, white oniony meat that is the leek’s truest claim to fame. If there’s no potato soup or vegetable stew pot simmering on the back burner, she or he can slice the greens, bag them, and store them in the freezer until soup’s on the menu.
The third time a cook meets a leek, that leek will end up in a steady stream of rinse water for a very long time. For reasons that are known only to the leek, all those months in the ground become lovingly documented by an almost breathtaking amount of dirt and sand pressed into the leek’s many layers. As leek-wise home cooks quickly discover, the vegetable clings to the dusty, dirty, gritty pearls of its former life, and nothing but a lot of rinsing and rerinsing will ever get the many layers grit-free enough for a savory pie.
Bringing out the sweet in the leek’s white bulb to prepare it for the pie can be easily done by roasting it in the oven or sautéing it in a little butter. An overcooked leek is a sad thing indeed, so sad that the garbage really is the best place to slide the slimy yuck. Leeks aren’t especially cheap, but once overcooked, there’s just no way to bring them around to the land of the edible.
Leeks that have been properly cooked until lightly browned, perhaps with a handful of red, white, or yellow onion cousins, or some sliced mushrooms are ready for their true destiny. There may not be any particular rhyme, but there are a thousand reasons for the flavor combinations cooks create to showcase this lowly vegetable pie. A base of beaten egg, cream, and goat, feta, or Gruyere cheese poured into a rich pastry crust creates a tart-like dish, while tickling a little salmon with lime zest, dill, and leeks and dressing it in a frock of puff pastry creates the kind of onion pie that has the power to bring dictators to their knees.
A deeply satisfying and perhaps more modest leek pie layered with some cooked sausage and shredded cheese into a thick "crust" of mashed potato sprinkled with Parmesan and run beneath the broiler makes a hearty dinner. Coconut milk instead of cream, a squeeze of lemon instead of the sausage, and a pastry shell instead of the mashed potatoes, and the leek pie has once again transformed, this time into an Indonesian meal. An Italian Crostada di Porri is a simple but utterly delicious blend of butter-soaked and thinly sliced sautéd leeks kissed with a little ricotta and hard, grated cheese thinly layered into a pastry shell.