Make the pudding using cream instead of milk. Beat with a whisk on high until filling is like a mouse and quite stiff.
Trim the berries, then slice some for the interior of the cake and cut some fans and halves as decorations.
Flavor and sweeten the cream and whip until stiff. DO NOT OVER BEAT.
Choose a shape and style and go to town. You can get plenty of good templates from the books here at the library and online.
Remember that these are supposed to look homemade but well put together and are quite beautiful. So have fun with it.