Leeks, those long, plump, green cousins to onions and shallots, are a cold-hardy crop.

With their mild, fresh, slightly sweet flavor and grassy aroma, leeks are just right for the shoulder season. They're immensely versatile and a staple in meatless dishes during the Lenten season, adding substance and taste to a range of light, warming dishes.

Leeks are beloved throughout the British Isles. They are to the Welsh what shamrocks are to the Irish and maple leaves are to Canadians. According to legend, early Welsh soldiers were encouraged to wear leeks on their helmets to identify themselves when battling the Saxons.

In our region, they may be overwintered, which explains why we can still find a few local leeks at our farmers markets and co-ops. Look for leeks with the greatest amount of white and light green on their stalks (the most usable portion). The dark green leaves are too tough to eat but are great when simmered in a stock.

To prepare a leek, trim off the whiskers, cut it in half horizontally and retain the pale green part. Then split the leek down the middle vertically. Rinse it thoroughly under cold running water to clean off any dirt.

Leeks are a workhorse in my kitchen. I like to make a leek confit to keep on hand as a base for a variety of pastas, soups, stews and pilafs, to garnish chicken and pork, top off pizza, and for savory tarts. Simply chop several large leeks and cook them gently in butter until very tender and silky. They become more concentrated versions of themselves.

Leek confit will keep for about a week in a covered container in the refrigerator. Or divide the confit into smaller portions and freeze to use when in need of a quick, comforting — and pretty — tart.

Leek and Cheddar Pie

Serves 8.

Note: You can use your favorite prepared crust or make your own (see recipe below). Make an extra batch of the leek confit to have on hand as a base for soups, stews, to toss with pasta or to serve on top of roast chicken or pork. From Beth Dooley.

• 4 to 5 medium leeks, about 2 to 2 1/2 lb.

• 2 tbsp. unsalted butter

• 1/2 tsp. salt, plus more if needed

• 1/2 c. whole milk Greek-style yogurt or sour cream

• 1 tsp. chopped fresh thyme or 1/2 tsp. dried thyme

• 1/4 tsp. freshly ground black pepper

• Generous pinch grated nutmeg

• 3/4 c. grated Cheddar cheese

• 1 prepared tart or pie crust (see recipe)

• Microgreens or chopped parsley for garnish

Directions

Preheat the oven to 375 degrees.

Clean the leeks by trimming off the root ends, slicing horizontally at the pale green part. (Reserve the top dark green part of the leek for stock.) Slice the leek in half vertically and run under cold water to thoroughly clean and then cut into thin slices.

Melt the butter in a large skillet over medium-low heat, add the leeks, and sprinkle with the salt. Cook, stirring occasionally, until the leeks are very tender and beginning to brown, about 10 minutes.

Turn the leeks into a medium bowl, stir in the yogurt, thyme, pepper, nutmeg and cheese; taste and adjust the seasonings. Turn the mixture into the prepared crust and spread it in an even layer. Set the pan on a baking sheet. Bake until it's bubbly and golden, about 35 minutes.

Let the tart sit at least 10 minutes before cutting. Serve hot, warm or at room temperature.

Butter Crust

Makes 1 (9- to 10-inch) crust.

Note: This all-butter crust is rich and flaky; leave enough time for the dough to chill. From Beth Dooley.

• 1 1/4 c. flour

• 1/8 tsp. salt

• 1 stick (1/2 c.) unsalted butter, chilled and cut into pieces

• 3 tbsp. ice water, or more if needed

Directions

In a large bowl, whisk together the flour and salt. Drop the butter pieces on top of the flour. Using a pastry cutter, two knives or your fingers, work the butter into the flour until it resembles cornmeal. (You can also use a food processor fitted with a steel blade.)

Toss in 2 tablespoons of the ice water and stir until the mixture comes together. Sprinkle in another tablespoon of water if the dough seems too dry. Turn the dough out onto a well-floured board and knead it a couple of times. Pat the dough into a disk (about 1/2 inch thick).

Wrap the dough in plastic and chill in the refrigerator about 30 minutes or up to 2 days.

When ready to use, unwrap the dough. Generously flour a work surface and, using a floured rolling pin, roll the dough out into an 11- to 12-inch circle, turning the dough 90 degrees between each pass. Fold the dough in half over the rolling pin and lift over a pie or tart pan then drop the dough into the pan. Unfold and gently press the edges, trimming as needed.

Beth Dooley is the author of "In Winter's Kitchen." Find her at bethdooleyskitchen.com.