In a mixing bowl, use an electric hand mixer to beat the egg until well-mixed, 1-2 minutes on low. Add softened butter, erythritol, and vanilla extract, then beat together for 1-2 minutes.
In a separate bowl, combine almond flour and baking soda, stirring until well-mixed.
Combine wet and dry ingredients and beat together until just starting to form a cohesive dough. Add almond milk and stir with a wooden utensil until the dough absorbs the milk and becomes moist.
Stir chocolate chunks into the dough until evenly distributed. Refrigerate the dough for about 20 minutes.
Preheat the oven to 350 F. Prepare a sheet pan lined with parchment paper or nonstick baking mat.
Shape the dough into 20 balls about 1-2 inches in diameter, using your hands to roll them into smooth balls.
Place them on the pan 1-2 inches apart from each other. Flatten the balls into cookie shapes.
Bake at 350 F until the cookies start turning lightly brown on top, about 20 minutes. Start monitoring after 15 minutes of baking and remove when done.