Preheat your oven to 350°F (175°C). Line an 8x8 inch baking pan with parchment paper, letting the edges hang over the sides for easy removal.
In a mixing bowl, whisk together the almond flour, cocoa powder, and salt.
In a separate bowl, combine the melted butter, sweetener, eggs, and vanilla extract. Stir well until smooth.
Gradually add the dry ingredients to the wet mixture, stirring until fully combined.
Pour about 3/4 of the brownie batter into the prepared baking pan, spreading it out evenly. Reserve the remaining batter for swirling on top.
In another bowl, beat the softened cream cheese with the sweetener until smooth. Add the egg and vanilla extract, mixing until creamy and fully combined.
Gently pour the cheesecake mixture over the brownie layer in the pan, spreading it evenly.
Drop spoonful of the reserved brownie batter on top of the cheesecake layer, then use a knife or skewer to swirl the brownie and cheesecake layers together for a marbled effect.
Place the pan in the oven and bake for 25-30 minutes, or until the cheesecake layer is just set and a toothpick inserted into the brownie layer comes out with only a few moist crumbs.
Let the brownies cool in the pan for about 15 minutes, then lift them out using the parchment paper and allow them to cool completely on a wire rack before slicing.