Add the softened butter and powdered sugar to a stand mixer bowl and mix on high with the whisk attachment for about 10 seconds. Scrape down the sides with a spatula.
Switch to the paddle attachment and add the fresh raspberries to the bowl. Mix on medium speed for 5-10 seconds until the berries break apart, but not burst.
Dump the butter mixture onto a long sheet of plastic wrap set over a long sheet of foil. Wrap and roll the butter mixture into log, twisting the foil ends as you go to make the log compact. Chill for at least 2 hours until firm and keep refrigerated until ready to use.