Line a baking sheet with parchment paper. This recipe is designed for a large baking sheet, around 9x13 inches. Set the sheet aside.
Fill a large pot with water (at least 3 inches deep) and let it simmer on a stove over medium heat. Do not boil the water.
Reduce the heat to low and add an extra heat-resistant bowl on top (or use the top pan if using a double boiler). Put the chocolate inside and stir frequently until it is smooth and melted. Add the extracts in after.
Pour the chocolate into your baking sheet and spread it evenly with a spatula or spoon. It should fill the sheet evenly.
(Optional) If you are trying to stack two different chocolate types, repeat steps 3-4 for your second chocolate variety.
Spread the vanilla Greek yogurt nicely over the chocolate base. It should fill the sheet evenly. For best results, try not to make the yogurt spread too thick.
Finally, scatter your crushed candy canes over the entire mixture. Make sure it fills as much area as possible.
Grab the baking sheet and store it in your freezer for no less than 2 hours. The Greek yogurt and chocolate must be completely solid when finished.
When ready to serve, take it out of the freezer and let it thaw for 5-10 minutes. Cut the bark into individual pieces and serve.