Preheat oven to 350°F

Line a 9×9 baking pan with parchment paper, or spray with non-stick spray.

Combine the melted butter, brown sugar, white sugar, and vanilla in a large bowl. Using a hand mixer, on low speed, mix for 1-2 minutes until well combined and the sugar crystals have dissolved.

Add the eggs and mix on low speed, just until the ingredients are combined.

Whisk the flour, baking powder, and salt together, then add to the bowl. Stir just until combined.

Fold the white chocolate chips and frozen raspberries into the batter.

Spread the batter into the prepared 9×9 pan.

Bake for 30-35 minutes until golden brown, the top feels set, the edges begin to pull away from the sides, and a toothpick inserted in the centre comes out mostly clean.

Move the pan to a cooling rack. Once cool, if you have used parchment, lift the bars out of the pan to slice. Otherwise, you can cut them in the pan and remove them.

Store in an airtight container at in the refrigerator for up to a week, or in the freezer for several months.