Preheat your oven to 350°F (175°C).
Line a baking sheet with parchment paper or a silicone mat.
In a large bowl, whisk the egg, then stir in the peanut butter, sweetener, melted butter, and vanilla until smooth and glossy.
In a separate bowl, mix almond flour, cocoa powder, baking soda, and salt. Break up any lumps in the cocoa or almond flour for a smoother dough.
Fold the dry mixture into the wet ingredients. The dough will be thick and a bit sticky.
If it seems too dry or crumbly, add 1 tablespoon of almond milk at a time until it holds together.
Stir in the sugar-free chocolate chips, reserving a few to press on top of the cookies for a nicer look.
Scoop the dough into 12 equal portions using a tablespoon or small cookie scoop. Roll into balls with your hands and place them on the prepared baking sheet, spaced about 2 inches apart.
Gently press each dough ball to about 1/2-inch thickness. These cookies won’t spread much, so shape them now to your preferred thickness.
Bake for 9–11 minutes until set around the edges and slightly soft in the center.
Do not overbake; they firm up as they cool.
Remove from the oven and let the cookies cool on the pan for 10 minutes. Transfer to a rack to finish cooling.