Preheat your oven to 350°F (175°C).
Grease a 9-inch round cake pan and line the bottom with parchment paper.
In a large mixing bowl, whisk together almond flour, cocoa powder, protein powder, erythritol, baking soda, and salt.
In another bowl, beat the eggs, then add applesauce and vanilla extract until well combined.
Combine the wet and dry ingredients, mixing just until no dry streaks remain.
Pour the batter into the prepared cake pan, smoothing the top with a spatula.
Bake for 25-30 minutes or until a toothpick inserted into the center comes out clean.
Allow the cake to cool in the pan for 10 minutes before transferring it to a wire rack.
Once cooled, frost as desired or enjoy plain.
