Place metal bowl in saucepan of barely simmering water. Melt chocolate and butter, stirring until smooth. Let cool to room temperature.
Sift flour, baking powder, and salt into another bowl. Beat into chocolate mixture until combined.
Pour into pan and sprinkle with berries
Bake on middle rack until lightly browned, but center is still soft when lightly touched.
Let cool completely in pan on rack.
Notes
Check at 45 minutes for doneness, but the cooking time could go another 5 minutes. Blondies have the best flavor when they are served at room temperature, but are easiest to cut when chilled.