Prepare and bake cake according to package directions, using a 9x13-inch glass baking pan. Remove cake from oven and let cool completely.
Place heavy whipping cream in a medium bowl. Using an electric hand mixer, beat heavy whipping cream until soft peaks form. Add cream cheese and powdered sugar and mix until well blended. Spread mixture evenly over cooled cake.
Pour as much or as little of the raspberry pie filling as you like over the whipped cream cheese layer. ( I slightly heated up the filling first in a saucepan to make it thinner and pourable. I only used about half of the can.) Then top cake evenly with fresh raspberries.
Place cake in refrigerator and let chill at least an hour or so before serving. Enjoy!