Preheat the oven to 350°F (175°C). Line a large baking sheet with parchment paper and set aside.

Place the melted butter, packed brown sugar, and granulated sugar in a large mixing bowl. Whisk until smooth and thoroughly combined.

Add the whole egg, egg yolk, and vanilla extract. Whisk again until the mixture looks smooth and glossy.

In a separate bowl, combine the all-purpose flour, baking soda, and salt.

Add the dry ingredients to the butter mixture. Fold or stir gently until just combined and no obvious streaks of dry flour remain. Avoid overmixing.

Fold in the white chocolate chips until evenly distributed throughout the dough.

Add the frozen raspberries last. Fold them into the dough gently and quickly so they don't completely break apart or thaw.

Using approximately a 1-ounce cookie scoop, portion the dough into rounded balls. Work quickly because the raspberries will begin releasing moisture as they thaw.

Arrange the cookie dough about 2 inches apart on the prepared baking sheet.

Bake the White Chocolate Raspberry Cookies for approximately 12 minutes, or until the edges are lightly golden and the centers are puffed but still appear slightly soft.

Let the cookies cool on the baking sheet for several minutes so the centers can set. Transfer carefully to a wire rack and allow them to cool further before serving.