Line an 11 x 15 sheet pan with parchment paper.
Starting with the white chocolate, place the chocolate melts and dark chocolate melting wafers in two separate microwave-safe bowls.
Heat 1 bag of the white chocolate wafers in 30-second increments at 50% power, stirring in between each increment until completely melted and smooth.
Pour the melted white chocolate out onto the prepared pan and smooth out into an even layer.
Add the Oreo cookies on top of the white chocolate before the chocolate starts to set. Press the cookies down into the chocolate gently.
Repeat the melting process with the dark chocolate wafers. Spread the melted chocolate over the top of the white chocolate and Oreo layer.
Repeat with the final bag of white chocolate wafers, spreading the melted chocolate on top of all of the other layers.
Sprinkle with peppermint bits.
Let the bark sit at room temperature until completely set and firm.
Cut the bark into large pieces and serve or store in a sealed container.