Combine the Swerve and cinnamon in a small bowl and mix well. Set aside.
Preheat oven to 325ºF and grease an 9x9 inch baking pan.
Whisk together the almond flour, sweetener, protein powder, baking powder, and salt in a medium bowl. Stir in the eggs, melted butter and vanilla extract. Add the almond milk and continue to stir until well combined.
Spread half of the batter in the prepared pan, then sprinkle with about two thirds of the cinnamon filling mixture. Spread the remaining batter over top and smooth with a knife or an offset spatula.
Bake 25 to 30 minutes, or until the top is golden brown and just firm to the touch. Remove from the oven.
Brush with the melted butter and sprinkle with the remaining cinnamon filling mixture. Let cool completely in the pan.
Frosting
In a small bowl, beat the cream cheese until smooth. Add the powdered sweetener, cream, and vanilla extract and beat until well combined.
Pipe or drizzle over cooled cake.
Notes
Storage Information: Store the cake, tightly covered, in the fridge for up to a week. It can also be frozen for several months.