So Simple Ideas
Preheat oven to 350°F. Grease 8×8 baking pan or line with parchment paper.
In large bowl, combine the butter, sweetener, cocoa, vanilla extract, and salt until well combined. Whisk in the eggs then fold in the flours. Reserve about ¼ cup of batter. Spread remaining batter into prepared pan
Beat together the cream cheese, sweetener, vanilla, and egg yolk until well blended. Spread cream cheese mixture evenly over brownie layer.
Drop reserved brownie batter over cheesecake layer. Swirl in with a knife.
Bake for about 30 minutes then transfer to a rack to cool.