Place the ice cream maker freezer container in the freezer 24 hours prior to making the ice cream.
Pour half of the churned strawberry ice cream base into a loaf pan (or a freezer-safe container, top with the raspberry puree and swirl the two mixtures together, not stirring too much. Then pour in the other half of the ice cream, top it with the remaining raspberry puree, and swirl again. Place plastic wrap, parchment or wax paper directly on top of the ice cream, cover and freeze for 1 hour for soft-serve consistency. For firmer ice cream, freeze for a few hours. (The time will depend on how firm you like your ice cream and how deep/shallow your ice cream container is - anywhere from 2-6 hours).
If you aren't using an ice cream machine, once the ice cream base reaches a soft-serve consistency, pour the raspberry puree over the ice cream and gently swirl the two mixtures together. Return to freezer and periodically stir (beat) the ice cream until completely frozen. It will likely take a few hours (from start to finish) to be ready.
Store leftover ice cream in an airtight container in the freezer for 1-2 weeks.
*Soak the cashews in water for at least 8 hours (or overnight) so they soften up and are easy to blend. To quick-soak cashews, pour boiling hot water over the cashews and soak for 1 hour uncovered. When the cashews are done soaking, drain the water and rinse the cashews thoroughly. (Note: if you do the quick soak, the ice cream will no longer be raw).
**Prep time does not include soaking the cashews (8 hours).