Preheat the oven to 350°F. Line an 8x8-inch baking pan with parchment paper, leaving some overhang on the sides for easy removal.
In a medium bowl, whisk together the almond flour, cocoa powder, sweetener, and salt until no lumps remain.
Add the melted butter, eggs, and vanilla extract to the dry ingredients. Stir until a thick, glossy batter forms. Fold in the sugar-free chocolate chips or espresso powder if using.
Spread about three quarters of the brownie batter evenly into the prepared pan. Reserve the remaining batter for swirling on top.
In a separate bowl, beat the softened cream cheese until smooth. Add the sweetener, egg, and vanilla extract, then mix until creamy and fully combined.
Spoon the cheesecake mixture over the brownie batter. Drop the reserved brownie batter in small dollops across the top.
Use a butter knife or skewer to gently swirl the cheesecake mixture and brownie batter together. Do not overmix if you want distinct swirls.
Bake for 28 to 32 minutes, or until the edges are set and the center has a slight jiggle. A toothpick inserted into the brownie portion should come out with a few moist crumbs.
Let the brownies cool completely in the pan. Chill for at least 1 hour before slicing into 16 pieces for the cleanest texture and neatest layers.