Prepare the pan: Heat the oven to 325°F. Grease and flour a 10-cup Bundt pan thoroughly.
Mix the batter: Combine the cake mix, pudding mix, sour cream, eggs, milk, oil, and vanilla until smooth.
Add chocolate: Fold in the white chocolate chips without overmixing.
Layer the filling: Add half the batter to the pan, dot with half the raspberry preserves, and swirl gently. Repeat with the remaining batter and preserves.
Bake: Bake for 50 to 60 minutes, until a skewer comes out with a few moist crumbs. Cool for 10 minutes in the pan, then invert and cool completely.
Make the frosting: Beat cream cheese and butter until creamy. Gradually add powdered sugar and vanilla, thinning with milk or cream if necessary.
Finish: Pipe or spoon the frosting over the cooled cake before slicing.