Chestnuts play a graceful role in sweetdishes, such as this golden strudel filled withsauteed apples and roasted chestnuts steepedin syrup -- a variation on marrons glaces.
Preheat oven to 350 degrees. Using a chestnut knife or a small paring knife, make an incision about 1/8 inch deep through the shell and into the flesh of each chestnut almost all the way around the circumference of the nut. Transfer to a chestnut pan or rimmed baking pan. Roast in the oven until the chestnuts are tender, about 35 minutes.Turn the oven off. Leaving the pan with the chestnuts in the oven, remove several at a time.Working quickly, place 1 chestnut in a towel. Holding both, peel chestnut while still hot. Remove and discard the shells and inner skin.Transfer chestnuts to a medium saucepan. Heat oven temperature to 375 degrees.
Add 4 cups water and 1/2 cup sugar to the chestnuts; place over high heat, and bring to a boil. Reduce heat, and simmer chestnuts until most of the liquid has been absorbed and the chestnuts are falling-apart tender, 40 to 45 minutes. Drain in a colander. Break chestnuts into small pieces, and set aside to cool.
In an electric mixer fitted with the paddle attachment, combine the flour and 1/2 teaspoon salt. Add the oil and remaining 3/4 cup warm water, and mix on medium-low speed until dough comes together, about 1 minute. Switch to the dough hook, and mix until the dough is smooth and shiny without sticking to your fingers when squeezed, about 5 minutes. Turn dough out onto a clean surface, and knead into a ball. Cover dough with a bowl, and let stand at least 1 hour or up to 4 hours.
Melt 3 tablespoons butter in a large skillet over medium-high heat. Add half the apples and 1/4 cup sugar, and cook, stirring frequently, until just tender and golden on the edges, 5 to 6 minutes. Transfer apples to a shallow bowl, and set aside until cool. Repeat cooking the remaining half of the apples in 3 tablespoons butter with remaining 1/4 cup sugar.
Place bread in a food processor; pulse until texture resembles coarse meal. Add bread crumbs to reserved apples, along with the reserved chestnuts, nutmeg, cinnamon, and the remaining 1/4 teaspoon salt. Toss to combine well; set aside.
Melt the remaining 4 tablespoons butter. Brush a baking sheet with melted butter, and set the remaining butter aside. Place a clean sheet or a very large apron on a clean surface about 36 inches square, and sprinkle with flour. Place the dough in the center, and roll into a 12-inch square. Cover dough with a damp towel, and let stand for 15 minutes. Remove the towel and slide both hands, palms down, under the dough. Lift dough, and begin stretching until it becomes too big to stretch on top of hands. Carefully set the dough back down on the cloth, making sure to spread the dough out without any wrinkles. Begin to pull the dough out in all directions, maintaining the square shape, until it is almost translucent and about 36 inches square.
Using a sharp knife or scissors, trim about 1/2 inch of the thicker edges off. The dough that remains should be only the very thinnest dough. Gently brush the butter evenly all over the dough, and arrange the apple-chestnut mixture on top, leaving a 1-inch border.
Lift the front edges of the cloth off the table, and flip the dough and apple-chestnut mixture over onto itself, enclosing the mixture.This first fold should be 3 to 4 inches wide. Continue folding the dough in this manner using the cloth until dough is completely rolled up and has the final edge on top. Carefully form dough into a C shape. Place the prepared baking sheet right next to the strudel, and flip strudel over onto the prepared baking sheet so that the top now becomes the bottom. Brush with butter, and sprinkle generously with sugar. Bake, rotating the pan halfway through baking, until the top is golden brown and the apples are tender, 45 to 50 minutes. Remove from oven, transfer baking sheet to a wire rack, and let stand until strudel is warm or at room temperature.