In a large mixing bowl, beat 8 oz of softened cream cheese together with two packs of vanilla instant pudding mix until smooth and creamy. Gradually pour in 2.5 cups of cold milk while mixing to prevent lumps. Continue mixing until fully combined, and then gently fold in 12 oz of Cool Whip, reserving 1/2 cup for later use, until no streaks remain.

Spread a thin layer of the reserved Cool Whip evenly across the bottom of a 9x13-inch pan. Layer graham crackers over the whipped cream, covering the entire surface, then scoop a generous layer of cream filling over the crackers, followed by an even distribution of sliced strawberries and blueberries.

Continue building your cake by repeating the layers, gently pressing down on the fruit layer with a spatula, then adding another layer of graham crackers, more cream filling, and a fresh layer of strawberries and blueberries until all ingredients are used, finishing with a layer of cream filling on top.

Cover the assembled cake tightly with plastic wrap or aluminum foil and refrigerate for at least 4 hours, preferably overnight, to allow the graham crackers to soften.

When ready to serve, melt 2 oz of white chocolate in a microwave-safe bowl, stirring in 20-second increments until smooth. Drizzle the melted chocolate over the top of the chilled cake. Cut into squares and serve chilled, garnished with extra berries.