Spray 9x13-inch baking pan with cooking spray and set aside. Set out cream cheese for the cheesecake layer and allow to soften as you prepare the brownies.

Make the brownies first: Melt butter and semi-sweet chocolate in a medium saucepan on medium heat, stirring constantly (about 6 minutes). Remove from heat and let cool to room temperature (about 15 minutes).

Stir Pyure Stevia Sweetener into cooled chocolate/butter mixture until combined. Add eggs one at a time, whisking until smooth after each. Whisk in vanilla. Gently fold in flour and salt. Pour batter into prepared pan, reserving 1/4 cup batter.

Preheat oven to 350. Make the cheesecake swirl: With a hand-held mixer on medium speed, beat the softened cream cheese, 1/4 cup Pyure Stevia Sweetener, egg yolk, and peppermint extract in a medium bowl until completely smooth. Manually stir in chocolate chips. Dollop spoonfuls of cream cheese mixture on top of brownie batter. Dollop with the last 1/4 cup brownie batter. Glide a knife through the layers, creating a swirl pattern. Sprinkle a few more chocolate chips on top.

Bake for 25-30 minutes, or until a toothpick comes out almost clean. Check them at the 25 minute mark to be sure. Allow brownies to cool completely before cutting into squares.