In a large bowl, cream the softened butter, brown sugar, and granulated sugar until light and fluffy (3-4 minutes).

Beat in the egg, extra egg yolk, and vanilla extract until fully combined.

In a separate medium bowl, whisk together the sifted flour, cocoa powder, baking soda, and salt.

Gradually add the dry ingredient mixture to the wet mixture, mixing on low speed only until combined. Do not overmix.

Gently fold in the high-quality dark chocolate chunks by hand.

Handle the whole raspberries *extremely gently* to avoid breaking. Carefully fold them into the dough, stopping immediately once they are distributed. (Toss frozen berries in a little flour before adding).

Scoop portioned dough balls onto a baking sheet lined with parchment paper. If reserved, press extra chocolate chunks into the top of each ball.

Cover and chill the dough balls in the refrigerator for at least 30 minutes.

While chilling, preheat oven to 350°F (175°C). Line another large baking sheet with parchment paper.

Space the chilled dough balls 2 inches apart on the prepared baking sheet. Bake for 11-13 minutes. The edges will be set, but the centers will look soft.

Immediately upon removal, press an extra chocolate chunk into any empty spaces on top of the hot cookie to create pools of melted chocolate.

Allow the cookies to cool on the hot baking sheet for 5-10 minutes until set, then carefully transfer to a wire rack to cool completely.