Preheat oven to 350 and grease an 8x8 pan. Set aside.
In a medium bowl, beat cream cheese until whipped. Mix in egg, vanilla and powdered erythritol until well combined. Set aside.
In a large bowl, beat eggs until they are frothy. Stir in erythritol and mix well.
In a small microwave safe bowl, melt butter and chocolate for 30 second intervals stirring between heatings, until chocolate is completely melted.
Add vanilla, salt, baking powder and melted chocolate to the bowl with the eggs and stir well.
Slowly stir in coconut flour (in 1 tbsp increments works best)
Once mixed, spread 3/4 of the brownie mixture into the prepared pan.
Spoon the cream cheese mixture on top and smooth it around.
Spread the rest of the brownie mixture on top of the cream cheese mixture to create a marbled look. (add 2 tbsp heavy cream before adding to help with marbling)
Bake 25-30 minutes or until a toothpick insterted in the center comes out clean