Preheat oven to 300 degrees F. Toast almond by scattering them on a baking sheet and bake for 15 minutes or until golden brown, stir occasionally. Set aside to cool completely. For the filling: In a medium bowl, stir together ? cup sugar, cinnamon, cornstarch. Add the peaches and blueberries, toss to coat. Set aside. Process the almonds in a food processor until finely chopped. In a medium bowl, combine almond, flour, sugar, and salt. Using a pastry blender, cut the butter into the flour mixture until pea sized crumbs form. Whisk together water and egg yolk. Sprinkle 1 Tbs of the egg mixture over the flour mixture and mix with fingertips. Repeat until all of the flour mixture is moistened. Gently knead the mixture until the dough comes together in a ball. Wrap dough ball in plastic wrap and freeze for 15 minutes. Preheat oven to 375 degrees F. Remove dough from freezer. Roll the dough out into a 12 inch circle on a lightly floured sheet of parchment paper. Do not trim the edges. Transfer the pastry and parchment paper to a baking sheet or invert the pastry into a 10 inch cast iron skillet that has been lightly floured. Use a slotted spoon to add the filling to the center of the pastry, leaving at least 2 to 3 inches of uncovered area around the edges. Fold the edges up over the filling, overlapping them in soft folds. (leave the center of the fruit filling uncovered) Mix the egg and water in a small bowl and brush the mixture over the edges of the pastry. Sprinkle the edges with coarse sugar. Bake for 30 to 35 minutes until the filling is bubbly and the crust is golden brown. Cool on a wire rack for 1 hour. For the topping: Toss peaches, blueberries, sugar, and lemon juice together. Set aside until crostata has baked and cooled. Spoon topping over the center of the crostata, covering the filling. Slice and serve.