For Crust: In a large bowl, combine the flour, sugar, and salt. Dice the butter into 1/2-inch pieces and scatter over the flour. Using a pastry blender or 2 forks, work the butter into the flour until the butter is about the size of small peas.

Drizzle the ice cold water over the flour mixture, and using a spatula gently stir it together until most of it has come together nicely. Knead the dough and gather all the loose bits, working as quickly as possible to keep it cold. Press the dough into a round disk, wrap once tightly with plastic wrap and refrigerate for at least 1 hour.

Preheat oven to 400 degrees F. Line a baking sheet with parchment paper.

In a medium bowl, combine the peaches, blackberries, brown sugar, flour, cinnamon, and nutmeg. Toss to combine.

On a lightly floured work surface roll the dough into a circle about 1/8-inch thick. Place the fruit mixture in the center of the crust, leaving a 1-inch border around the sides. Gently lift the galette border over the fruit, and overlap the dough where necessary and gently pinch to keep the folds together.

In a small bowl, mix together the egg and water. Lightly brush the egg wash on the edge of the dough, and sprinkle with the turbinado sugar.

Bake the galette for 35 to 40 minutes, or until the crust is golden brown and fruit is tender. Cool on baking sheet on a wire rack. Serve warm drizzled with caramel sauce and ice cream if desired.

For the Caramel: In a large heavy bottomed sauce pan, combine the sugar and water. Heat the mixture over medium-high heat without mixing. Once the edge start to brown, occasionally swirl the pan. Continue to cook the sugar mixture until it is a deep amber colour. About 5 to 10 minutes.

Remove from the heat and add the heavy cream while whisking constantly. The mixture will bubble vigorously! Whisk in the whisky and the salt. Transfer to a container with a lid, and cool completely uncovered. Will keep covered in the refrigerator for about 2 weeks. Heat slightly in the microwave for serving.