Preheat oven to 350°F. Line an 8x8” baking pan with parchment paper so that paper hangs over the sides. Set aside.
Melt the butter in a small saucepan over medium-high heat. Continue to cook, stirring occasionally, until the butter has brown specks throughout. Remove from heat and transfer to a medium mixing bowl to cool slightly.
Whisk together flour, baking powder and salt in a large bowl. Set aside.
Add the sugar, eggs and vanilla to the butter, and whisk to combine. Pour the wet ingredients into the flour mixture and stir until just combined.
Pour the batter into the prepared pan, spread into an even layer, and sprinkle with the berries.
Bake for 40-45 minutes or a toothpick inserted into the center comes out mostly clean with some moist crumbs. Allow the blondies to cool completely in the pan on a wire rack before slicing.