Start by preheating your air fryer to 310ºF, getting it ready for perfect baking.
In a medium-sized bowl, gently whisk together all the dry ingredients: the almond flour, brown sugar replacement, collagen peptides, baking soda, and a pinch of salt until they are nicely combined.
Next, stir in the melted butter, egg yolk, and vanilla extract until the mixture is well blended and forms a dough. Then, carefully fold in the sugar-free chocolate chips.
Gather the cookie dough into a ball and place it on an 8-inch square of parchment paper. Gently pat it down into a disc about 5 inches in diameter.
Carefully transfer the parchment paper with the cookie disc onto your air fryer crisper rack. Set your air fryer to "Bake" and cook at 310ºF for 8 to 10 minutes, or until the cookie is puffed and beautifully golden brown.
Once cooked, carefully remove the cookie and let it cool completely on the parchment paper before enjoying. This ensures it sets perfectly!