Line an 8x8 baking dish with parchment paper and set it to the side. Unwrap the candy canes. Place the candy canes in a large zip lock bag, seal the bag, then use a rolling pin to crush all of the candy canes. You can roll or gently bang the rolling pin over the candy canes, leaving a mixture of smaller and larger pieces. Set the crushed candy to the side.
In a small bowl, add the chopped semi-sweet chocolate and ½ tsp cooking oil. Melt the chocolate in the microwave, stirring every 20-30 seconds. Keep an eye on the chocolate as it melts. The moment it starts to mix smoothly, it's ready. Don't let it overheat or else it will become thick and lumpy. Every microwave is different. It took approximately 1:25 seconds for mine to smoothly melt. Remove the bowl from the microwave and stir in ¼ tsp of peppermint extract.
Pour the melted chocolate into the parchment lined baking dish. Spread the chocolate evenly around with a small spatula or spoon. Place the dish in the refrigerator for 10-12 minutes until the chocolate is mostly set. You don't want the chocolate to fully set or else the white chocolate layer will not adhere properly.
In a separate bowl, add the chopped white chocolate and the remaining ½ tsp cooking oil. Melt the white chocolate in the microwave, stirring every 20-30 seconds. Keep an eye on the chocolate as it melts, being careful not to overheat it. Remove the bowl from the microwave and stir in ¼ tsp of peppermint extract.
Remove the baking dish from the refrigerator and pour the melted white chocolate on top of the semi-sweet chocolate. Spread the white chocolate evenly around with a small spatula or spoon.
Now sprinkle the crushed peppermint candy on top of the melted white chocolate. Place the baking dish back in the refrigerator until the chocolate is fully set, about 1 hour.
Once the bark is fully set, remove the baking dish from the refrigerator and lift the peppermint bark out of the parchment paper. Break the bark into small and large pieces or cut it with a sharp knife. If your bark is too hard to break, let it sit at room temperature for about 10 minutes so the chocolate can soften a bit. Store any leftovers covered in the refrigerator for 2-3 weeks. Enjoy!