Preheat your oven to 350°F and line a baking sheet with parchment paper.
In a large bowl, cream together with hand mixer the butter, granulated sugar, and brown sugar until light and fluffy
add the egg and vanilla extract mixing until smooth.
Add the flour and switch to a wooden spoon or sturdy mixing spoon. Stir just until the flour is incorporated. This helps prevent overmixing and keeps the cookies soft.
Gently fold in the frozen raspberries, being careful not to crush them too much. A few raspberry streaks throughout the dough create beautiful swirls.
Cover the bowl and chill the dough in the refrigerator for 30 minutes to 1 hour. This helps the cookies hold their shape and creates a thicker, bakery-style cookie.
Scoop about 2 tablespoons of dough onto the prepared baking sheet, leaving about 2 inches between each cookie.
Bake for 12–15 minutes, or until the edges are lightly golden and the centers are just set.
allow the cookies to cool on the baking sheet for 5 minutes, then transfer them to a wire rack to cool completely