Preheat the oven to 325F and lightly grease a 9x13 baking pan.
In a large bowl, combine the almond flour, sweetener, protein powder, baking powder, and salt. Add the butter, egg, and vanilla extract and stir to combine well. Press into the bottom and partway up the sides of the prepared baking pan.
In another large bowl, beat the cream cheese and butter together until smooth. Beat in the sweetener until well combined, then beat in the eggs and vanilla until smooth.
Pour the filling over the crust. Bake 35 to 45 minutes, until the filling is mostly set, but the center still jiggles, and the edges are just golden brown.
Remove and let cool, then dust with powdered Swerve and cut into bars.
To make this with keto boxed cake mix (Swerve or Good Dee's), simply mix the cake mix with 1 egg and 1/2 cup melted butter. Then press the crust into the pan and follow the filling directions.