Begin by preheating your oven to 180 °C (356 °F).
In a large mixing bowl, combine the almond flour, erythritol, cocoa powder, and baking powder. Whisk these dry ingredients together until well blended.
In a separate bowl, beat the eggs, then add the whole milk, espresso, and vanilla extract. Mix the wet ingredients thoroughly.
Gradually pour the wet mixture into the dry ingredients, stirring continuously to create a smooth batter. For the best low-carb chocolate cake, ensure there are no lumps.
Gently fold in the dark chocolate chips, reserving a handful for later.
Grease a 20 cm (8-inch) round cake pan and pour in the batter. Sprinkle the remaining chocolate chips on top.
Bake for approximately 20 minutes, or until a toothpick inserted into the center comes out clean. The key to achieving a moist keto chocolate cake is to avoid overbaking.
Allow the cake to cool in the pan for 10 minutes before transferring to a wire rack. Once completely cooled, top with sugar-free whipped cream for an extra indulgent touch.