Apple and Plum Croustade (Croustade aux Pommes et Prunes)

Preparation

1. Step 1

   Prepare the pastry: Mix the flour and salt in a large bowl.

2. Step 2

   Cut butter into cubes of various sizes and add to the flour. Using your fingers, work the butter into the flour and salt by pinching together with your fingers and thumbs, leaving pieces of different sizes, from almond- to pea- to lentil-size lumps. This should be a very coarse mixture.

3. Step 3

   Make a well in the mixture and add ⅔ cup/150 milliliters cold water. Mix quickly with a large spoon until you can form a ball (adding 1 to 2 tablespoons more water if needed). The pastry will be very soft.

4. Step 4

   Turn the dough out onto a well-floured board or surface and knead just enough to form a smooth ball. With a floured rolling pin, roll the dough out into a rectangle about ½-inch thick, making sure to use enough extra flour for the board.

5. Step 5

   Fold the rectangle into thirds then roll out into another ½-inch-thick rectangle. Fold that rectangle into thirds and roll into a rectangle again. Repeat the process two more times. Wrap the dough in plastic film and let the dough rest in the refrigerator while you prepare the filling.

6. Step 6

   Prepare the filling: Peel, core and thinly slice the apples about ¼-inch thick. Pit and slice the plums into generous ½-inch-thick pieces and add both fruits to a large bowl.

7. Step 7

   Add the sugar, cinnamon, ¼ teaspoon salt and, if using, a generous splash (about 1 tablespoon) of Armagnac to the fruit and toss to combine. Let sit while you roll out the dough.

8. Step 8

   Heat the oven to 400 degrees. Make an egg wash by beating the egg with a teaspoon of water. Set aside.

9. Step 9

   Roll out the pastry: Cut the dough rectangle in half crosswise. Roll one half out to about ¼ inch thick (roughly 13-by-9-inch) and place on a sheet pan or cookie sheet lined with parchment paper. Roll out the other half to the same size (this will be the top crust), slide onto a pan lined with parchment and let rest in the fridge while you add the filling to the bottom crust. (If using store-bought pastry, roll each sheet out to a 13-by-9-inch rectangle and continue preparing as instructed.)

10. Step 10

    Arrange the filling evenly across on the surface of the bottom pastry, leaving roughly 1 to 1½ inches uncovered on the edges. (You should have a layer of fruit no more than 2½ inches high; enjoy any extra filling on the side or with ice cream.) Cover with the top pastry and fold up the rim of the pastry and crimp as desired. With a paring knife, cut a few small slits in the top crust to vent the pie. Brush with the egg wash and sprinkle generously with the turbinado sugar and nuts.

11. Step 11

    Bake the croustade until very golden brown, 30 to 40 minutes. (Expect that there will be sugary, juicy, delicious leakage that runs out around the pan.)

12. Step 12

    When the croustade is cool enough to handle, slide it off the pan and parchment onto a wire rack. Cool completely, at least 3 hours. Serve, cut into big squares, at room temperature or rewarmed.