Spread 2 slices of bread with 1 tablespoon of butter. Place sourdough slices, butter-side-down, and top with half the sliced brie. In a small bowl, mash the blackberries with a fork and divide between the two sandwiches, spooning on top of the sliced brie. Arrange the sliced peaches on top of the smashed blackberries, finally topping with remaining sliced brie. Top each sandwich with the corresponding slice of bread and spread 1 tablespoon of butter on top of each.

Heat a large skillet over medium heat. Add the sandwiches and cook until golden brown, approximately 3-4 minutes each side.

Best served immediately.