Line a baking pan with foil, letting some hang over the sides.
Spray with cooking spray.
Melt the chocolate chips in a double boiler over medium low heat.
Pour evenly onto the lined pan and spread with a spatula.
Sprinkle with 1/4 cup of crushed peppermint candy.
Place in refrigerator until firm.
Next, melt white chocolate chips in a double boiler over medium low until almost melted. Remove from heat and stir until melted.
Stir in extract.
Pour over chocolate layer and spread quickly.
Sprinkle with remaining crushed peppermint candies.
Chill until both layers are firm.
Lift foil out of pan and shake off excess candy.
Peel foil from bottom of peppermint bark.
Cut into squares.