Smash peppermint candy in a baggie or using a rolling pin.
Melt semisweet chocolate until smooth, using your preferred method.
With a spatula, spread melted chocolate as evenly as possible on the parchment paper, about ¼-inch thick. Place in the fridge for 10-15 minutes.
Melt white chocolate until smooth, stirring in peppermint extract. If the white chocolate isn't melting smoothly, stir in a splash of heavy cream or whole milk at a time until smooth.
Drizzle and spread white chocolate over the chilled semisweet layer.
Sprinkle the crushed peppermint candy on top evenly before the white chocolate sets.
Refrigerate for an hour.
Break into desired size pieces.
Notes
White chocolate isn't technically chocolate and therefore doesn't always melt smoothly. Try splashing in some heavy cream as you go until smooth.
Use any sort of candies you like. This method also works will with crushed nuts or other goodies.
Line your pan with parchment or a silicone mat, not foil, for easy removal.
Store in the fridge if your house has hot spots, like how we have a wood stove.