Preheat the oven to 425°F (220°C).
In a large mixing bowl, combine the sliced peaches and raspberries. Add the sugar, flour, lemon juice, vanilla extract, cinnamon, and salt. Gently toss the mixture until the fruit is well coated.
Pour the fruit mixture into the pie crust, spreading it evenly. Dot the top with small pieces of butter.
Cover the pie with a second pie crust or create a lattice top with strips of dough. If using a full crust, cut a few slits in the top to allow steam to escape.
Bake in the preheated oven for 15 minutes. Reduce the temperature to 350°F (175°C) and continue baking for an additional 30-35 minutes, or until the crust is golden brown and the filling is bubbly.
Remove the pie from the oven and let it cool for at least 2 hours before serving to allow the filling to set.