Begin by preheating your oven to 350° Fahrenheit, and grease a nine-inch cake pan with either avocado oil or olive oil.
In a large mixing bowl combine the almond flour, cocoa, protein powder, sweetener, baking powder, espresso powder, and salt until evenly mixed.
Once mixed add the melted butter, eggs, vanilla, and almond milk to the dry mixture. Whisk again until you have a smooth batter with few to no lumps.
Pour the batter into the prepared pan, and spread it out evenly using a spatula. Bake for 20-25 minutes or until the edges have begun to pull away from the pan and a toothpick when inserted into the middle comes out clean.