Pre-heat oven to 425.
Peel and slice peaches (peach skins slip off if you place fruit in boiling water for 30 seconds or so) into a large mixing bowl. Scrape vanilla bean into a small bowl and mix with brandy. Pour brandy mixture over peaches, and sugar and spices, stir. If your fruit is very juicy, add cornstarch.
Spread peaches in a 8x8 baking dish and scatter blueberries over them. Bake at 425 for 10 minutes.
While the fruit is baking, sift together the flour, salt, and baking powder. Add sugar. Cut in butter until mixture is even crumbly, and slowly add just enough boiling water to give the batter a goopy texture (about 1/4 cup).
Remove fruit from oven and spoon batter on top. Don't worry about evenly covering fruit; batter expands while cooking. Put cobbler back in 425 degree oven and bake 25 minutes or until biscuit is golden brown.
Adjust sugar levels depending on the sweetness of the fruit. Fully ripe fruit gives the best flavor, but slightly under-ripe fruit has a firmer texture.