Line a large baking sheet with parchment paper or a silicone baking mat. Set it aside.

Place the dark chocolate in a microwave-safe bowl. If using coconut oil, add half of it now. Microwave in 30-second intervals, stirring in between, until the chocolate is completely smooth.

Pour the melted dark chocolate onto the prepared baking sheet. Use a spatula to spread it into a thin rectangle, about 1/4 inch thick.

Place the baking sheet in the refrigerator for about 15 to 20 minutes. The chocolate should be firm but not rock hard.

While the dark chocolate sets, melt the white chocolate in a clean microwave-safe bowl using the same 30-second interval method. Stir in the remaining coconut oil if using.

Once the white chocolate is smooth, stir in the peppermint extract.

Remove the dark chocolate from the fridge. Pour the white chocolate over the top and spread it gently with a clean spatula to cover the dark layer.

Immediately sprinkle the crushed candy canes over the wet white chocolate. Lightly press them down with your hand to make sure they stick.

Return the tray to the refrigerator and chill for at least 1 hour, or until the bark is completely solid.

Once set, lift the parchment paper off the tray. Use your hands to break the bark into irregular pieces or use a sharp knife to cut it into squares.