Combine the cream cheese, sugar, and raspberry preserves in a mixing bowl. Using a whisk, mix together until all ingredients are fully combined and the sugar starts to dissolve.
Add in the heavy whipping cream and milk. Whisk until all ingredients have combined well. This may take a minute or two because the raspberry preserves mixture is quite thick.
Add in ½ of the raspberries that have been cut in half. This will be about 6-8 raspberries based on the size.
Once all ingredients have been added (except the mix-ins) pour into an empty Ninja Creami pint container and freeze for 24 hours.
After 24 hours, remove the pint from the freezer. Remove the lid.
Place the Ninja Creami pint into the outer bowl. Place the outer bowl with the pint in it, into the Ninja Creami machine and turn until the outer bowl locks into place. Push the ICE CREAM button. During the ice cream function, the ice cream will mix together and become very creamy.
Once the ice cream function has ended, turn the outer bowl and release it from the Ninja Creami machine.
Using a spoon, create a hole through the center of the ice cream that goes from top to bottom. This hole is where you will add the mix-ins. Add in the ¼ cup of raspberries and 3 white chocolate truffles. Be sure to cut the raspberries in ½ and the truffles in ¼. These mix-ins will not get broken into smaller pieces during the mix-in function so you want to make sure they are in pretty small pieces.
Place the outer bowl with the pint back into the Ninja Creami machine and lock it into place. Choose the MIX-IN function.
Once the Ninja Creami completes the MIX-IN cycle, remove the outer bowl from the machine.