Preheat the oven to 350°F (175°C).
In a large bowl, combine the almond flour, cocoa powder, erythritol, baking soda, and salt.
In another bowl, whisk together the almond milk, melted coconut oil, vanilla extract, and apple cider vinegar.
Pour the wet mixture into the dry ingredients and stir until just combined.
Grease and line an 8-inch round cake pan with parchment paper.
Pour the batter into the prepared pan and spread it evenly.
Bake for 25-30 minutes or until a toothpick inserted in the center comes out clean.
Allow the cake to cool in the pan for 10 minutes before transferring to a wire rack.
Serve as is or frost with your favorite low-carb icing if desired.