In the bowl of a stand mixer (or use a handheld), cream cold butter until smooth. If you need to let it warm up a bit, feel free, but I have had more luck with these with my butter still cold.
Add the sugar and vanilla and cream together.
Add the eggs and mix well.
Add in flour, cocoa, salt and baking soda until combined.
Stir in the chocolate chips, white chocolate chips and frozen raspberries (do not let thaw)*. Cover bowl with plastic wrap and let dough chill in the freezer for 30 minutes.
Preheat oven to 325 degrees F.
Shape dough into approximately 1" balls and place on a lightly greased cookie sheet. Bake for 10-13 minutes until the tops just appear dry and slightly puffed -- the cookie will sink down as it cools. Make sure you take them out just as they finish setting, because we don't want overbaked cookies.
Notes
*Keeping the raspberries frozen prevents them from becoming complete mush. They will still break and smush a little bit as you mix them in -- do not worry. I prefer it this way because the raspberry flavour is spread more evenly throughout the cookie, but you will still have some chunks of raspberry.