Preheat the oven to 400 degrees.
Remove one sheet of phyllo from under the wrap to a clean work surface. Brush it with half of the melted butter. Lay the second sheet of phyllo on top and brush with the remaining butter. Cut the phyllo in half lengthwise, then quarter lengthwise, to make 8 rectangles.
Place 4 of the rectangles on a baking sheet lined with parchment paper and sprayed lightly with nonstick cooking spray. Place the remaining rectangles on top of each, making four 4-layered pastries. Arrange about 10 to 12 peach slices on each pastry and sprinkle 1 teaspoon of brown sugar over each. Bake for 10 minutes.
Remove from the oven and sprinkle each pastry with an additional teaspoon of brown sugar. Return to the oven and bake 5 to 7 minutes more, until the sugar has melted and is bubbly.