Line baking sheet with parchment paper and have two microwave-safe bowls on stand-by.
Melt semi-sweet chocolate in a microwave-safe bowl until completely melted (15 to 30 second increments, stirring).
Once melted, stir in 1/4 teaspoon of peppermint extract and canola oil (divided).
Quickly pour melted chocolate onto baking pan and smooth layer with spatula.
Place baking pan in the freezer for about 3 to 5 minutes (You don't want it to be completely set). Or place in refrigerator for about 8 minutes.
Melt white chocolate in a microwave-safe bowl until completely melted (15 to 30 second increments, stirring).
Once melted, stir in the remaining 1/4 teaspoon of peppermint extract and canola oil.
Next, pour melted white chocolate onto baking pan, and carefully smooth out layer.
Sprinkle crushed candy canes and Oreo cookies on top of white chocolate.
Refrigerate bark for about 30 minutes.
Once completely set, remove chocolate from pan and discard parchment paper.
Sprinkle any remaining crushed candy canes (and cookies if you would like) over layer of white chocolate.
Break/cut into pieces. Serve and enjoy!