Prepare cake mix according to package instructions, using egg whites for a white cake. Sprinkle ½ cup white chocolate chips over the top of the batter before baking.

Bake in a 9x13-inch pan according to package instructions. Let the cake cool slightly.

Use the handle of a spoon to poke holes all over the warm cake. Pour raspberry syrup over the cake.

Melt ⅔ cup white chocolate chips and stir in the sweetened condensed milk. Pour over the cake.

Let the cake cool completely. Spread a thin layer of buttercream frosting over the cake and freeze for 5 minutes. Then, finish frosting with the remaining buttercream.

Sprinkle the remaining white chocolate chips over the top. Serve and enjoy!