Coat 1 1/2 qt. loaf pan with cooking spray. Combine marshmallows, sugar, cream, butter and salt in a medium sauce pan; cook on low heat; stir constantly over heat to melt butter and marshmallows. Boil 5 minutes; stir occasionally. Combine 1/4 cup chocolate chips with raspberry preserves in microwave 15-20 seconds until smooth; set aside. Remove mixture from heat. Add 1 1/2 cups white chocolate chips and vanilla; stir. Pour into pan. Drop spoonfuls of raspberry mixture on top. Use a knife to swirl. Allow to set up.