Leek and Celery Pie

PreparationMake phyllo dough: Stir together flour and salt in a large bowl, then make a well in center and add water, yogurt, 1/2 cup oil, and vinegar. Stir until a soft dough forms, then knead on a work surface (do not dust with flour) until smooth and pliable, about 4 minutes. Form dough into a ball and put in an oiled bowl, then turn to coat. Cover bowl with plastic wrap and let dough stand at room temperature 1 hour. Make filling: Wash leeks in a bowl of cold water, agitating them, then lift out and drain well in a colander. Heat 1/4 cup oil in a deep 12-inch heavy skillet or a 5- to 6-quart heavy pot over moderately high heat until hot but not smoking, then sauté leeks and celery with 1/2 teaspoon salt, stirring frequently, until softened and translucent, 10 to 12 minutes. Transfer to a bowl and cool, stirring occasionally, 10 minutes. Put oven rack in middle position and preheat oven to 375°F. Stir herbs into leek mixture along with cheeses, pepper, and remaining 1/2 teaspoon salt. Lightly beat eggs with remaining 3 tablespoons oil in a small bowl, then stir into leek filling. Assemble pie: Brush baking pan with 2 tablespoons oil. Divide dough in half. Roll out 1 half on a floured surface with a floured rolling pin into a 19- by 14-inch rectangle. Fold rectangle loosely into quarters and transfer to baking pan, then unfold dough and fit into pan, leaving a 1-inch overhang. Spread filling evenly in pan. Roll out remaining dough on floured surface with floured rolling pin into a 20- by 15-inch rectangle. Lift dough and drape it over filling, leaving it slightly wrinkled. Roll edge of bottom crust over top to form a rope edge all around pie. Brush top of pie with remaining 2 tablespoons oil. Score top crust into serving pieces with a sharp knife (mark crust but do not cut through it). Bake pie until golden brown, 50 to 60 minutes. Cool to room temperature in pan on a rack, about 1 hour. Cooks' notes:· Dough can be made 3 days ahead and chilled in a sealed plastic bag. Bring to room temperature before rolling out. · Pie can be baked 4 hours ahead and kept at room temperature.

PreparationMake phyllo dough: Stir together flour and salt in a large bowl, then make a well in center and add water, yogurt, 1/2 cup oil, and vinegar. Stir until a soft dough forms, then knead on a work surface (do not dust with flour) until smooth and pliable, about 4 minutes. Form dough into a ball and put in an oiled bowl, then turn to coat. Cover bowl with plastic wrap and let dough stand at room temperature 1 hour. Make filling: Wash leeks in a bowl of cold water, agitating them, then lift out and drain well in a colander. Heat 1/4 cup oil in a deep 12-inch heavy skillet or a 5- to 6-quart heavy pot over moderately high heat until hot but not smoking, then sauté leeks and celery with 1/2 teaspoon salt, stirring frequently, until softened and translucent, 10 to 12 minutes. Transfer to a bowl and cool, stirring occasionally, 10 minutes. Put oven rack in middle position and preheat oven to 375°F. Stir herbs into leek mixture along with cheeses, pepper, and remaining 1/2 teaspoon salt. Lightly beat eggs with remaining 3 tablespoons oil in a small bowl, then stir into leek filling. Assemble pie: Brush baking pan with 2 tablespoons oil. Divide dough in half. Roll out 1 half on a floured surface with a floured rolling pin into a 19- by 14-inch rectangle. Fold rectangle loosely into quarters and transfer to baking pan, then unfold dough and fit into pan, leaving a 1-inch overhang. Spread filling evenly in pan. Roll out remaining dough on floured surface with floured rolling pin into a 20- by 15-inch rectangle. Lift dough and drape it over filling, leaving it slightly wrinkled. Roll edge of bottom crust over top to form a rope edge all around pie. Brush top of pie with remaining 2 tablespoons oil. Score top crust into serving pieces with a sharp knife (mark crust but do not cut through it). Bake pie until golden brown, 50 to 60 minutes. Cool to room temperature in pan on a rack, about 1 hour. Cooks' notes:· Dough can be made 3 days ahead and chilled in a sealed plastic bag. Bring to room temperature before rolling out. · Pie can be baked 4 hours ahead and kept at room temperature.