CRUST:
Mix finely ground Oreos and butter, should resemble wet sand.
Firmly press the crumb mixture into rectangular pan to form a crust on the bottom and up the sides. The bottom of a glass may be helpful to press the crumb mixture firmly down.
Let chill in refrigerator until ready to fill, minimum 30 minutes.
GANACHE:
In small sauce pan heat heavy cream to almost boiling, pour in white chocolate. Turn off heat. Stir until chocolate is completely melted. Remove from heat, pour in crushed candy cane, stir.
Pour into bowl to cool down.
Repeat with semi-sweet chocolate.
ASSEMBLY:
Once ganaches are cooled (can be warm but not hot) remove crust from refrigerator.
Gently and slowly pour the white chocolate ganache down one long side of the tart shell.
Moving quickly repeat on the other side with the semi sweet chocolate.
Take a spatula and swirl down the middle to create a swirled pattern down center, mixing the two ganaches slightly (see photo).
Sprinkle on broken candy cane pieces or crushed candy canes.
Refrigerate until set or until ready to serve.