Set aside a rolling pin, 9-inch pie plate, pastry brush, bench scraper, kitchen scissors, and plastic wrap. You will need these items as you prepare the pie dough.

In a medium bowl, whisk together the flour, sugar, and salt until well combined.

Add the cold butter pieces and toss to coat, separating any pieces of butter that stick together.

Using your thumb and forefinger on both hands, press the butter pieces into 1/4-inch thick discs. If the butter becomes greasy, allow the mixture to chill in the refrigerator for 15 minutes before continuing.

Add the cold water and stir together with a spatula until just absorbed.

Press the dough together (use the sides of the bowl to assist)--it will be slightly shaggy.

Transfer the dough to a well-floured countertop and dust the dough with flour.

Using a floured rolling pin, roll the dough into a rectangle measuring roughly 10-inches long x 6-inches wide. Lightly brush away any excess flour with a pastry brush. Fold the 6-inch sides inward towards each other so that both edges meet in the center.

Fold the dough in half to form a square. This laminates the dough, resulting in a flakier pie crust.

Gently shape the dough into a disc and roll into a circle measuring 14-inches in diameter.

As you are rolling the dough, rotate it by quarter turns, lifting it regularly with a bench scraper to prevent sticking, and dusting with flour as necessary.

If the dough becomes too soft or difficult to work with, chill in the refrigerator for 10 to 15 minutes before continuing.

Carefully transfer the dough to a 9-inch pie pan. Gently lift and nudge the dough into the edges of the pan without stretching the dough.

Using kitchen scissors or a knife, trim the overhang so that it goes just about 1/2-inch to 3/4-inch past the edge of the pan.

Fold the edges under and crimp as desired. Brush off excess flour with a pastry brush, cover the dough surface with plastic wrap, and chill in the refrigerator for a minimum of 2 hours (or overnight).

Start by preheating the oven to 400 degrees Fahrenheit with a rack in the center position. Set aside a half sheet pan for later.

In a medium mixing bowl, combine the all-purpose flour, rolled oats, brown sugar, cinnamon, ginger, allspice, and salt. Add the cubed butter and toss to coat.

Using your fingertips, work and press the butter into the dry ingredients until the butter is dispersed and there is a good mixture of smaller and larger crumbs. Chill in the refrigerator until ready to use.

In a large mixing bowl combine the peeled and chopped pear, brown sugar, all-purpose flour, lemon juice, vanilla extract, cinnamon, ginger, allspice, and salt.

Remove the shaped and chilled crust from the refrigerator.

Gently transfer the pear filling into the pie shell, spreading it into an even, thick layer.

Sprinkle the crumble topping over the pear mixture (it will be thick and generous!).

Brush the edges of the pie dough lightly with the egg wash. Place the pie pan on a half sheet pan to catch any bubbling juices during baking.

Bake at 400 degrees Fahrenheit for 30 minutes; reduce the oven to 350 degrees Fahrenheit and continue baking for an additional 30 to 40 minutes, or until deeply golden and the pear filling is just bubbling.

Set pan on a rack and allow pie to cool and set for at least 2 to 3 hours before serving. Serve slightly warm with vanilla ice cream or a drizzle of heavy cream.