Spray 15x10x1-inch pan with cooking spray. Reserve 1/2 cup of the semisweet chocolate chips. In 2-quart saucepan, heat remaining semisweet chocolate chips, the dark chocolate chips and 1/3 cup cream over medium-low heat, stirring constantly, until melted. Pour into pan; spread evenly. Refrigerate.
Meanwhile, in 3-quart saucepan, heat butter, pudding mix and 1/2 cup cream to boiling over medium heat, stirring constantly. Remove from heat; stir in peppermint extract, vanilla and powdered sugar, beating well, until mixture is smooth. Spread evenly over cooled chocolate layer; freeze until firm, 15 to 20 minutes.
Place reserved 1/2 cup chocolate chips in small resealable freezer plastic bag. Microwave on High 45 to 55 seconds, turning bag over after 30 seconds. Squeeze bag until chips are melted and smooth. Cut small tip off one corner of bag, and drizzle over top. Immediately sprinkle with chopped candy. Cut into 15 rows by 5 rows.