Line a rimmed cookie sheet with parchment paper, then set aside.
In a double boiler (or I use a metal bowl over a saucepan of simmering water), first melt the chopped dark chocolate, stirring constantly until the chocolate is fully melted.
Pour the dark chocolate evenly over the parchment paper, spreading it out thinly.
Set the chocolate aside to cool until set but not hard, about 15 minutes.
After this time, melt the white chocolate. Melt it using the same method as the dark chocolate.
Pour the white chocolate directly onto the dark chocolate, spreading it out (using a spatula) to completely cover the dark chocolate. See picture above.
Get your kids ready and have them sprinkle on the crushed peppermint.
Let the bark cool completely before breaking it apart. At least 1 - 2 hours.
After the bark has hardened, have fun with the kids and break the bark apart into small-medium pieces.
Store up to 2 weeks in an air tight container, with the peppermint bark pieces layered between wax paper.