Preheat the oven to 350 degrees and line an 8 x 8 or 9 x 9 pan with parchment paper leaving an overhang on 2 sides or spray the pan with cooking spray.
Combine butter and chocolate in a small saucepan over low heat until melted, stirring often. Remove from heat and let cool for 5 minutes.
Pour the butter and chocolate mixture into a medium bowl and add sugar. Stir to combine.
Add the eggs and stir until combined.
Add the cocoa powder, flour and salt and stir until there are just barely streaks of flour remaining.
Add the white chocolate chips and raspberries and carefully stir into the brownie batter.
Pour the batter into the prepared pan, smoothing the top and bake for 20-25 min until set in the middle and done on the sides and a toothpick inserted contains moist crumbs.
Transfer to a wire rack to cool completely in the pan. Sprinkle the brownies with the crushed freeze-dried raspberries if desired.
Once cooled remove the brownies from the pan (if you used parchment paper) and slice into bars.