Preheat the oven to 400°F. Place the pear slices in a medium bowl and toss them with 2 tablespoons of the sugar; set aside. To make the crust, combine the flour; salt and 1 tablespoon of the sugar in a food processor. Pulse a few times, then add the butter and pulse until the mixture looks pebbly. With the food processor running, add a few drops of water at a time through the feed tube, just until the mixture starts to pull together.

Form a disc with the dough and wrap it in plastic. Freeze it for 15 minutes to allow the butter to firm up. Dust your work surface, rolling pin and the dough with flour Roll the dough out Into a circle about 12 inches in diameter and 1/8 inch thick. If the dough begins to stick to the work surface, add more flour to the surface and keep turning the dough as you roll it out.

Transfer the dough to a baking sheet. Arrange the pear slices in a single layer on the pastry, leaving a 1½-inch border. Fold the edges of dough up over the pear slices. Brush the rim of the dough with the egg.

Sprinkle the remaining sugar over the dough and pears. Bake for 45 to 50 minutes, until the fruit is tender and the pastry is golden. Remove the galette from the oven and let it cool slightly Serve warm or at room temperature.