Preheat oven to 350 degrees. Grease and flour two (9-inch) round cake pans. Place two wire rack over two baking sheets; set aside.
CAKE: In a large bowl, whisk together cake mix and vanilla pudding mix. Make a “well” in the center. Add eggs, water and cooled melted butter. Beat on medium speed for about 1 minute until batter is smooth and thick. Spread evenly into prepared pans.
Bake for 20 -25 minutes or until tops spring back when lightly touched, or a toothpick inserted in center of cake comes out clean. Let cake cool in pans for 5 minutes, remove to wire rack to cool completely.
RASPBERRY TOPPING: Pour Jell-O mix into a medium bowl. Pour boiling water over Jell-O, whisk until dissolved. Pour into a large, shallow pan and set in the refrigerator until slightly thickened, about 15-20 minutes.
Meanwhile, place coconut in a food processor and pulse a few times until coconut is in smaller pieces. Pour into a bowl and toss with cornstarch until coated; set aside.
Trim the domed tops from cooled cakes. Dip cakes one at a time into the slightly thickened Jell-O mixture, working quickly so the cakes don’t get too soggy and fall apart.
Place cakes back on wire racks and gently press coconut onto the top of each cake. Let cakes set for 1-2 hours.
FILLING: In a large bowl, beat 1/2 cup softened butter, vanilla, and whipping cream on medium low speed. Add marshmallow cream and beat on medium until smooth. Slowly beat in confectioners’ sugar until just combined. Increase speed to high and beat for one minute, until fluffy. Pipe frosting over bottom cake layer. Place top layer over frosted bottom layer. Slice and serve.