Place the butter in the oven in an 8 x 8 baking dish until it is melted.
In a medium mixing bowl, combine the peaches and blueberries with one cup of the sugar. Set aside.
In a separate mixing bowl, combine the remaining cup of sugar, flour, baking powder, salt and milk.
Remove the melted butter from the oven. Pour the batter over the top of the butter. Do not stir.
Pour the fruit over the top of the batter. Again, do not stir.
Bake for one hour until the crust has risen to the top and is golden brown.
Notes
Storage: Allow the blueberry peach cobbler to cool completely. Cover the top with plastic wrap or aluminum foil and store in the refrigerator for up to four days.Freezing: I have never tried to freeze this cobbler in its unbaked state, so I can with confidence recommend doing this. A baked peach cobbler can be frozen for up to three months. Cover the top with plastic wrap or aluminum foil.Reheating: Allow the peach cobbler to thaw in the refrigerator before reheating. Preheat the oven to 350 degrees. Bake for 20-30 minutes until the cobbler is heated through. Individual servings can also be reheated for 1-2 minutes in the microwave; however, the crust will not be as crisp.