To make the crust: Place flour into a mixing bowl with the sugar, and the paddle attachment. Give the flour and sugar a quick mix. Slowly add the butter cube by cube, and mix on low until it forms a wet-sand-like consistency. Alternatively you can use a pastry cutter and cut the butter into the flour / sugar mixture. Add the salt, mix. Add the cold water one tablespoon at a time. Dough is ready when it is firm and not sticky. 

To make the filling: combine all ingredients into a bowl and toss until incorporated.  Roll dough out on flat surface that has been dusted with flour. Roll out in a circle that’s about 10-12 inches wide all around. Spoon peach mixture into middle of the pastry, leaving about 3 inches of the edge for folding. Gently move around the crust and fold it in to just about an inch over the peaches, leaving the middle of the galette open. Keep folding the next part on top of the previous part, and so on until the entire crust is folded inward. Brush with egg wash and sprinkle with raw sugar. 

Bake at 350° for 30-35 minutes, or until middle is bubbly and edges are a nice golden brown. Allow to cool slightly before serving. 

Top with whipped cream or ice cream if desired. Served 6-8. Store covered in the refrigerator for up to four days. Enjoy!