Preheat the oven to 325F and grease 2 4-inch diameter ramekins well. (You can easily bake this recipe in a countertop convection oven too...just remember to reduce the temperature by 25F).
In a medium bowl, whisk together the almond flour, sweetener, coconut flour, protein powder, baking powder, pumpkin pie spice, and salt.
Whisk in the pumpkin puree, egg, melted butter, and vanilla extract until well combined. Divide the batter between the two ramekins and smooth the tops.
Bake 20 to 25 minutes, or until the center is set. Remove from the oven and let cool 10 minutes, then run a sharp knife around the edges of the ramekins and turn out the layers onto a wire rack to cool completely.
In a medium bowl, beat the cream cheese, sweetener, and vanilla extract until well combined and smooth. Beat in a few tablespoons of cream, and add more as necessary for a spreadable consistency.
Place one layer of cake on a serving plate and spread with frosting. Place the second layer on top and spread the remaining frosting all over the top and the sides of the cake. Chill 1 hour to help set the frosting.
Garnish with a few chopped, toasted pecans, if desired.