01 - Preheat the oven to 350°F. Line a 9-inch square baking pan with parchment paper, leaving overhang for easy removal.
02 - In a medium bowl, combine crushed chocolate cookies and melted butter. Mix until evenly moistened.
03 - Press the mixture firmly into the bottom of the prepared pan to form an even crust. Bake for 8 minutes. Remove from oven and set aside.
04 - In a large bowl, beat the cream cheese and sugar until smooth and creamy.
05 - Add the egg, egg yolk, vanilla extract, peppermint extract, and salt; beat until fully combined.
06 - Mix in the sour cream and food coloring (if using) until the mixture is smooth and evenly colored.
07 - Fold in the mini chocolate chips gently.
08 - Pour the cheesecake filling over the pre-baked crust and smooth the top. Bake for 30–32 minutes, or until the center is just set and the edges look slightly puffed.
09 - Remove from the oven and cool completely at room temperature. Then refrigerate for at least 2 hours until fully chilled.
10 - Once chilled, lift the cheesecake out of the pan using the parchment overhang. Cut into 16 bars and serve.