Preheat your oven to 375°F (190°C).
In a large bowl, combine the sliced peaches, blueberries, sugar, cornstarch, cinnamon, nutmeg, and salt. Toss everything together until the fruit is coated in the mixture.
Pour the melted butter into a 9x13 inch baking dish.
In a separate bowl, whisk together the flour, sugar, baking powder, and salt. Gradually stir in the milk until the batter is smooth.
Pour the batter evenly over the melted butter in the baking dish.
Spoon the fruit mixture evenly over the batter.
Bake the cobbler for 45-50 minutes, or until the crust is golden brown and the fruit is bubbling.
Let the cobbler cool for a few minutes before serving with a scoop of vanilla ice cream.
Enjoy your delicious Peach and Blueberry Cobbler!