Preheat the camp oven to 350 degrees F (175 degrees C). Spray an 8- by 8-inch (20- by 20cm) baking pan with non-stick spray.
In a medium bowl, stir together the butter, sugar, flour, and salt. The mixture will look dry and crumbly.
Press the dough into the prepared pan. Bake until slightly browned along the edges, about 10 minutes. Set aside.
Raspberry Topping
In the same medium bowl, stir together the sugar, flour, baking powder, and salt. Add the raspberry chipotle sauce, raspberries, egg whites, and egg. Whisk together until smooth.
Pour the raspberry filling over the crust. Bake until the top is bubbly and slightly brown on the edges, 25 to 30 minutes.
Cool to allow the raspberry filling to set. Slice into squares and sprinkle with the confectioner's sugar and top with fresh raspberries.