Line a baking sheet with parchment paper or non-stick foil.
Using a microwave safe dish, melt semi-sweet chocolate.* Turn your microwave to 50% power and microwave chocolate in 30-second increments, stirring after each increment.
When chocolate is fully melted, add in peppermint extract if using and stir until combined. Pour melted chocolate onto the lined baking sheet. Using a rubber spatula, smooth chocolate out.
Melt white chocolate in the same way as the semi-sweet chocolate.* Gently pour over semi-sweet chocolate. Carefully, spread white chocolate into an even layer, making sure it doesn’t mix with the semi-sweet chocolate.
Sprinkle with crushed peppermint. Refrigerate for at least 30 minutes or until chocolate is firm.
Using a sharp knife cut/break into bite-size pieces.
* You don’t need to use semi-sweet chocolate! You can just melt the white chocolate, add in the peppermint extract (if using) and pour onto a baking sheet, and sprinkle with the peppermint candies. Using the semi-sweet chocolate will make the bark a little thicker and obviously uses semi-sweet chocolate which pairs nicely with the white. Add as much or as little peppermint extract as you want! Taste as you add so you know when to stop.