Prepare a 9-inch by 9-inch baking pan by greasing the pan with oil or butter.
Preheat oven to 350ºF
In a large mixing bowl add in the melted butter, oil, and sugars, mix until light and fluffy.
Then add in the eggs and egg yolk one at a time until fully incorporated.
Add in the vanilla extract and mix it into the batter.
Next, sift in the flour, baking powder, and salt.
Mix into the batter just until incorporated, without overmixing.
Fold in most of the raspberries and white chocolate chips.
Pour the batter into the prepared baking pan.
Sprinkle with raspberries
Bake for 28-35 minutes, until a toothpick poked into blondie, comes out clean.
Cool in pan for 15-30 minutes, then remove onto a wire rack to cool completely.