Preheat oven to 350°F. Lightly grease a 9-inch pie dish.
In a medium bowl, whisk together flour, salt, baking powder, and sugar.
Stir in melted butter, milk, and vanilla extract until just combined.
Pour the batter into the prepared pie dish and spread evenly.
Evenly top the batter with sliced peaches and blueberries.
Bake for 55–60 minutes or until the top is golden and a toothpick inserted comes out clean.
Let the pie cool slightly before serving. Best enjoyed warm or at room temperature.