Line a cookie sheet with parchment paper. Set aside.
In a plastic bag, add 1 cup of the golden grahams cereal and crush into small pieces. Set aside.
In a glass bowl, microwave white chocolate melting wafers in 30 second increments, stirring until melted. Alternatively, melt using a double boiler on the stove top. Once melted, add crushed golden grahams from previous step and stir to combine.
Pour white chocolate mixture onto parchment lined baking sheet. Using a spatula, spread into a thin, even layer. Your chocolate should be about ¼-1/3" thick with no holes. This will make a 10-12" oval.
Quickly sprinkle your remaining golden grahams cereal and mallow bits evenly on top. Tap baking sheet lightly on the counter to help your toppings sink into the melted chocolate.
In a glass bowl, microwave milk chocolate melting wafers in 30 second increments, stirring until melted. Alternatively, melt using a double boiler on the stove top. Use a spoon to drizzle milk chocolate evenly across the bark.
Place cookie sheet into refrigerator or freezer to harden, about 10-15 minutes. Break into pieces and store in a sealed container for up to 2 weeks.