110-oz packagewhite chocolate or vanilla melting chips
Chopped peppermint bark
Spray a 9-inch tart pan with baking spray and set aside. Preheat oven to 350°F.
Add chocolate wafers to a food processor and process until fine crumbs. Add butter and stir until crumbs are evenly coated.
Press crust mixture into tart pan and bake for 12 minutes. Remove from oven and let cool completely.
In a double broiler (or a heat-safe bowl over a small saucepan with 1-inch of simmering water) combine chocolate chips and whipping cream. Stir until melted and smooth.
Measure 1/2 cup ganache and pour it into the chocolate crust. Loosely cover tart pan and move to the refrigerator to chill. Transfer remaining chocolate ganache into a bowl and refrigerate until completely cool. (You might also want to reserve a couple tablespoons of this to drizzle over the top of the tart later!)
Rinse double broiler or bowl/saucepan and repeat with white chocolate and 3/4 cup whipping cream. Transfer white chocolate ganache to a bowl and stir in peppermint extract. Refrigerate until completely cool.
When ganaches have set, transfer chocolate ganache to the bowl of a stand mixer fitted with the whisk attachment. Whip until fluffy, about 5 minutes. Spoon whipped ganache over the chocolate in the tart crust and smooth with an offset or rubber spatula.
Rise mixer bowl and whisk attachment. Repeat with white chocolate ganache until fluffy. Spread over chocolate ganache.
Toppings: you can use whatever you want here, but top tart with a drizzle of chocolate ganache, chopped peppermint bark, chocolate curls or shavings, sprinkles, crushed peppermints, etc.
Chill for about an hour before serving. You might need to let it thaw slightly or cut with a hot knife. Store covered in the refrigerator.