HEAT oven to 375°F.
COMBINE peaches, 3/4 cup sugar and tapioca in large saucepan. Stir in water. Bring to boil on medium heat, stirring occasionally. Stir in raspberries. Pour into 9-inch square baking dish; dot with 1 Tbsp. butter.
MIX flour, 2 Tbsp. sugar, baking powder and salt in medium bowl. Cut in remaining butter until mixture resembles coarse crumbs. Stir in milk until mixture forms soft dough. Drop by heaping tablespoonfuls onto hot fruit mixture.
BAKE 30 min. or until biscuit topping is golden brown.