Line pie plate with one half pie dough. Prick the bottom all over with a fork. Roll the other half flat and return both to the fridge.
Preheat oven to 375° F (190°C) in a regular oven, or 350°F (180°C) in a convection oven.
Mix sugar, syrup, salt, cornstarch, allspice, extract and liqueur (if using). Stir together until sugar and cornstarch dissolves.
Section pears with a handheld apple slicer if you have one, slicing peels off and making each slice relatively even. Toss to coat after each pear to prevent oxidization.
Put pear mixture in the chilled pie dough. Dot with butter.
Beat the egg with a tsp. of water to make an egg wash.
Paint the edge of the dough with the egg wash, then add the other rolled out pie dough in top. Brush egg wash all over. Pinch the edges together.
Cut vents with a knife. Sprinkle with more maple sugar on top. Cover loosely with aluminum foil. Place or a cookie sheet to catch any spillage.
Bake for 45 minutes covered. Remove foil, then bake for another 30-45 minutes, or until golden brown and the juices are bubbling up through the cracks.
For deep dish, add another 4 pears and 2 tbsp. maple sugar. Don’t add more liquid.
Use pears that are just ripe or almost ripe. Very ripe or over-ripe pears become mushy when cooked.
If a pear is grainy, don’t add it to your mix. Just toss it or eat it raw.