Prepare the brownie mix according to the package directions in a parchment-lined 8x8-inch baking pan. Bake until the brownies are set, then let them cool completely. If you’re in a hurry, place the pan in the refrigerator once it’s no longer hot to help them cool faster.

Add the softened cream cheese and powdered sugar to a mixing bowl. Beat until smooth and creamy. Mix in the vanilla and peppermint extract.

Gently fold the whipped topping into the cream cheese mixture until light and fluffy. Fold in about half of the crushed peppermint candies.

Spread the peppermint cheesecake mixture evenly over the cooled brownies. Sprinkle the remaining crushed peppermint candies and mini chocolate chips over the top, if using.

Refrigerate for about 1 hour, or until the cheesecake layer is firm enough to slice. Use the parchment paper to lift the bars from the pan, then cut into 12 squares.