Put all the dough ingredients but the ice water in a large bowl.

With clean hands, quickly smoosh the mixture together, or use a pastry blender with and up and down motion, until the ingredients look like cracker crumbs with lumps the size of peas and almonds.

Sprinkle ice water over the mixture and stir lightly with a fork.

Squeeze a handful of dough to see if it holds together. Mix in more water as needed.

Divide the dough in half and make two chubby discs about 5 inches (12cm) across.

Wrap the discs separately in plastic wrap and chill for an hour.

Once the dough has been chilled, preheat the oven to 425°F (225°C).

In a medium bowl, place the plums, sugar, nutmeg, salt, Cointreau, flour, and tapioca, and mix until the fruit is well coated.

Take out the dough discs and let them temper until they feel slightly soft to the touch and easy to roll out. Unwrap one disc and place it on a well-floured board, pastry cloth, parchment paper, or plastic wrap.

Sprinkle some flour on the top of the disc. Thump the disc with your rolling pin several times. Turn it over and thump the other side.

Sprinkle some flour onto the top of the dough as needed to keep the pin from sticking, and roll the crust out from the center in all directions.

When the dough is 1-2 inches (3 to 5 centimeters)larger than your pie pan, brush off the extra flour on both sides.

Fold the dough over the top of the pin and lay it in the pie pan carefully.

Don’t worry if the crust needs to be patched together. Paint a little water where it need to be patched and “glue” on the patch piece.

Pour the filling into the unbaked pie shell and dot with the knob of butter, cut into pieces. It’s okay to tear pieces off with your fingers as well.

Roll out the remaining disc of dough, lay it over the fruit, and cut 5-6 vents on top, or cut strips and make a lattice top. Trim excess dough from the edges and crimp.

Lightly brush some of the egg wash over the entire pie, including the edges.

Bake for 20 minutes at 425°F (220°C).

Reduce the heat to 350°F (175°C) and bake for 30-35 minutes more.

When there are about 10 minutes of bake time left, open the oven, pull the pie out, and quickly and even sprinkle the top of the pie with sugar.

If the filling is not making steady bubbles, turn the heat back up to 450°F (230°C) for 5 minutes to help it along.

If needed, cover the pie loosely with a vented piece of aluminum foil, shiny side down, before you turn the heat up.

Remove the pie from oven and cool as long as you can before serving, so the filling can set up.