Preheat oven to 450°
Peel and slice the peaches and place them in a bowl with the blueberries.
Stir in cornstarch, granulated sugar, lemon zest, and lemon juice and set it aside.
Invert a cookie sheet and cover it with parchment paper.
Open one of the pie crusts and place it in the middle of the cookie sheet.
Using a rolling pin, roll it out just until it gets to the edges of the cookie sheet.
Place peaches in the middle of the pie crust, in a circular fashion overlapping. Continue moving out to the edges of the crust, leaving about 1-2 inches of crust without fruit.
Once the crust is filled with peaches, add the blueberries randomly.
Pull up the crust in folds and continue working around the pie until all of the edges are folded in and on top of the fruit around the edges. Make sure you leave a large opening, the crust is not supposed to cover the entire fruit filling.
Beat the egg and brush the entire crust with the egg wash. Be generous because this not only helps the crust get golden brown, but it also acts as the "glue" for the almonds.
Shingle the almonds on the crust until the entire crust is covered. *NOTE - if you don't want to take the time to shingle them, you can randomly place them all over the crust.
Sprinkle the Turbinado sugar all over the galette and bake for 25-35 minutes.
Let it cool for 15 minutes before serving.