Preheat your oven to 350°F

Begin by preparing the peaches. Using a knife, cut around the center of each peach and separate the halves from the stone pith. Lay each peach half cut side down on a cutting board and slice into 1/4" slices.

Add the peach slices to a mixing bowl.

Next, add the flour, sugar and cinnamon to the sliced peaches. Gently turn with a spatula to coat the peaches evenly. 

Then, line a baking sheet with parchment paper.

Next, Lay out the pie crust on the baking sheet and arrange the coated peach slices to leave approximately a 2" boarder of crust. 

Lastly, fold the edges of the crust up over the peach mixture and pinch the edges into place so that they do not separate during baking. 

Next, make an egg wash by beating an egg together with the water and brush the crust.

Bake the galette for 1 hour, until hot and bubbly and the crust is golden brown.

Allow the galette to cool for 20 minutes before serving.

Serve with whipped cream or a scoop of ice cream, if desired.