Grease a 9-inch-square baking pan + set aside.

Microwave 1/3 cup chocolate chips/morsels + 1/3 cup butter in small, uncovered, microwave-safe bowl on medium-high (70%) power for 30 seconds; Stir. If necessary, microwave at additional 10- to 15-second intervals, stirring just until chocolate is melted.

Stir crushed cookies into melted chocolate mixture. Press onto bottom of prepared pan.

Refrigerate for 10 minutes or until firm.

Meanwhile, beat 1/3 cup butter, milk, 1/2 teaspoon peppermint extract + vanilla extract in medium mixer bowl until smooth. Gradually beat in powdered sugar until smooth + creamy. Add food coloring, 1 drop at a time, until desired color is reached. Spread powdered sugar mixture evenly over cookie crumb layer.

Microwave remaining 1 2/3 cups chocolate chips/morsels, 1/3 cup butter + 1/2 teaspoon peppermint extract in small, uncovered, microwave-safe bowl on medium-high (70%) power for 30 seconds; Stir. If necessary, microwave at additional 10- to 15-second intervals, stirring just until chocolate is melted. Let stand for 10 minutes. Spread chocolate layer evenly over powdered sugar mixture.

Refrigerate for at least 2 hours.

For easier cutting, allow bars to sit at room temperature for 10 minutes.