Preheat oven to 350 and line an 8x8 inch pan with foil and spray well with cooking spray.
Prepare cheesecake batter. Use a hand mixer to cream together cream cheese and sugar until smooth. Add sugar and peppermint and mix well. Add egg and egg white and mix. Stir in flour. Set batter aside.
Prepare brownie batter. Add flour, cocoa powder, and salt to a bowl and whisk to combine. In another large bowl combine brown sugar, oil, heavy cream or half and half, vanilla, and eggs and mix until smooth. Slowly mix in flour mixture until completely combined.
Pour all but 1/2 cup of brownie batter into prepared pan. Spread cheesecake layer evenly on top of brownie layer. Drop tablespoons of reserved brownie batter on top of cheesecake layer. Use a knife to swirl batter. Bake about 25 minutes, until top is set. Allow to cool completely before cutting into bars. Store in airtight container, keep refrigerated.
Store in airtight container in the fridge up to 1 week.