Pour both types of cream, sugar and extract into a heavy saucepan and bring to a boil on low heat.
Chop up the bittersweet chocolate and put into a bowl.
Pour boiling cream mixture over the chocolate and stir until smooth.
Place bowl in the fridge for 2 3/4 - 3 hours to firm up.
Using a teaspoon, scoop out firm chocolate and roll into walnut size truffle. (it gets a little messy, but completely worth it!)
Drop truffle into a bowl or container of crushed candy canes and completely cover. I usually shake the container to completely cover instead of rolling it with my fingers to avoid getting candy cane all over your fingers.
Put completed truffles into an airtight container and place in the fridge or freezer to firm up.