12oz (1½ cups) good-quality semisweet chocolate, chopped into ½ inch pieces
1½ tsp peppermint extract (2 x ¾ tsp)
1 lb (2 cups) good-quality white chocolate, chopped into ½ inch pieces
3 candy canes or 12 round hard peppermint candies, crushed
Instructions
Line a 9" x 13" baking dish with aluminum foil, shiny-side up; smooth out any wrinkles.
Heat 1 inch of water in a saucepan over low heat until steaming.
Put all but ¾ cup of the semisweet chocolate in a heat-proof bowl. Set the bowl over the saucepan of steaming water (do not let the bowl touch the water) and stir until one-third of the chocolate is melted.
Remove the bowl from the suacepan; keep the steaming water over low heat. Gradually stir the reserve ¾ cup semisweet chocolate into the bowl, a few pieces at a time, until all the chocolate is melted. Return the bowl to the saucepan, 5 to 10 seconds at a time, to help melt the chocolate, if needed. Do not rush this step: it may take up to 10 minutes to melt the chocolate.
Wipe off any moisture from te bottom of the bowl. Stir ¾ tsp peppermint extract into the chocolate, then quickly pour into the prepared baking dish and spread in an even layer. Firmly tap against the counter to remove any airbubbles. Set aside at room temperatre until almost set; about 10 minutes.
Put all but 1 cup of white chocolate into a large, heat-proof bowl and repeat melting process over the steaming water; dry off the bottom of the bowl.
Stiry in the remaining ¾ tsp peppermint extract; pour over the semisweet chocolate and spread in an even layer.
Sprinkle immediately with the crushed candy canes, gently pressing them into the white chocolate.
Set aside at room temperature until firm; about 1 hour. Lift the bark out of the pan using the foil and break into pieces. Store in an airtight container at room temperature for up to 2 weeks.