Combine the cream cheese, sugar, and Creme de Menthe in a mixing bowl. On medium-high speed, mix until the sugar and Creme de Menthe are well incorporated (1-2 minutes). Scoop the cheesecake filling into 20 1-Tablespoon-sized portions onto a small sheet pan lined with parchment paper. Alternatively, you can pipe the filling out using a piping bag as well. It's okay if there is a some cream cheese leftover. Place the sheet pan of the cheesecake portions into the freezer until they are frozen and very firm, 1-2 hours. In the meantime, make the dough.

In a large bowl sift together the flour, cocoa, baking soda and salt, set aside. Using a mixer fitted with the paddle attachment, beat butter and sugars for 3 minutes until fluffy. Next, beat in the egg and peppermint extract and mix until combined.

Add the dry ingredients and beat on medium-low speed just until combined, or mix by hand with a wooden spoon. Don’t overmix – mix just until combined. The batter will be thick and sticky.

Roll cookie dough into 20 pre-formed balls. Chill the dough balls in the refrigerator for 30-60 minutes. This will help keep the batter less sticky when stuffing your cookies. After chilling, remove from refrigerator and flatten each dough ball into a small disc. If they’re too cold/hard to handle, leave them sit for a few minutes on the counter. Flatten all dough balls into discs.

Preheat oven to 350F/180C degrees. Line two large baking sheets with parchment paper. Set aside.

Once the cheesecake centers are frozen, peel them off of the parchment paper and place each one onto the center of your cookie dough discs. Seal up the sides of the dough by pinching it together so the no cheesecake is exposed. If desired, dip the tops of the dough balls in a shallow bowl of mint chocolate chips and press down slightly to adhere well. (If freezing the dough balls for later, stop here.)

Drop rounded balls of dough (the size of 2 tablespoons) onto prepared baking sheet, leaving about 3 inches (8 cm) between each cookie. Bake for about 10 minutes, just until the edges start to set and the cookies have spread perfectly. Leave to cool on the pan for 10 minutes and then carefully transfer to a wire rack to cool completely.

Serving: These cookies taste best at room temperature or served cold from the refrigerator. They are even better the day after they are baked!

Storing: Store the cookies in an airtight container in the refrigerator for maximum freshness and food safety! These cookies keep well up to 4 days once baked.