Preheat the oven to 350°F. Grease a baking pan and line it with parchment paper, preferably a 9-inch square mold.

In a large bowl, mix melted butter with brown sugar, vanilla extract, and the egg. Incorporate well to achieve a homogeneous mixture.

Add the flour and baking powder to the mixture. Mix well until all the ingredients are fully incorporated.

Finally, add the fresh raspberries and chopped white chocolate to the mixture and gently stir to distribute them evenly.

Pour the batter into the prepared mold and spread it evenly.

Bake in the preheated oven for 25 minutes or until the top is golden. Avoid overbaking to maintain the moistness of the brownies.

Once baked, remove from the oven and let it cool in the mold for 15 minutes.

Transfer the blondies to a rack to cool completely.

Once the blondies are completely cool, cut them into squares.