Ingredients

makes one 9-inch tart

　　All-purpose flour, for work surface

　　1 sheet frozen puff pastry from a standard package (17.3 ounces), thawed

　　2 tablespoons unsalted butter

　　5 leeks, white and pale-green parts only, washed well, and cut crosswise into 1/2-inch-thick pieces

　　1/4 cup nonfat buttermilk

　　2 teaspoons Dijon mustard

　　Coarse salt and freshly ground pepper

　　5 ounces fresh goat cheese, crumbled

　　1 large egg yolk

　　1 tablespoon heavy cream or water

　　

Step 1

Line a baking sheet with parchment paper, and set a 9-inch tart ring (about 2 inches deep) on top; set aside. On a lightly floured work surface, roll out the puff pastry to about 1/8 inch thick. Using a sharp paring knife, trim the dough to a 13-inch round, and lay it over tart ring. Fit into the ring, and fold in the edges against the inside of the ring, pressing gently to seal. Refrigerate 20 minutes.

　　

Step 2

Preheat the oven to 400°F. In a large nonstick skillet set over medium heat, melt the butter. Add the leeks; cook, stirring, until soft, about 7 minutes. Add the buttermilk and mustard, and cook until slightly thickened, about 2 minutes. Season with salt and pepper. Remove from heat; set aside.

　　

Step 3

To assemble the tart, layer the goat cheese and the leek mixture on the chilled pastry, ending with goat cheese. In a small bowl, beat together the egg yolk and cream. Brush the pastry with egg wash, and bake until golden, about 35 minutes. Serve warm.

　　Reprinted with permission from The Martha Stewart Living Cookbook: The New Classics by Martha Stewart Living Magazine, copyright © 2007. Published by Clarkson Potter, a division of The Crown Publishing Group.Buy the full book from Amazon.