Heat the oven to 350 and butter an 8 x 8 inch baking pan
In a large bowl, whisk together the melted butter and sugar until smooth.
Add the egg, egg yolk, vanilla, and salt and whisk to combine.
Stir in the flour until just combined.
Stir in the white chocolate chips until evenly distributed.
Carefully fold in the raspberries, taking care not to break them up too much. Pour into the prepared pan and spread the thick batter evenly.
Bake 23 to 27 minutes, or until a toothpick inserted in the center comes out with moist crumbs.
Let the blondies cool completely in the pan and cut into squares.
Doubling the recipe
This recipe is easily doubled by making twice the batter and using a 9 x 13 inch baking pan instead of 8 x 8. Change the number of servings in the recipe card from 9 to 18 and it will adjust all the ingredient quantities for you.
Store refrigerated in an airtight container for 3-4 days.
Store the cut blondie bars in a freezer bag or wrap them up in plastic wrap and keep them frozen in an airtight container. These will last you for about three months. Just thaw them overnight in the fridge before serving.