In a saucepan, place milk, peanut butter, sweetener, and cocoa powder. Bring to a boil, stirring continuously. Cook for a moment until the ingredients are combined, and the sweetener is dissolved. Set aside.

After a moment, add the rolled oats to the saucepan. Mix well. Cook for a short time, stirring constantly (until the mixture slightly thickens), then set aside to cool.

Spoon about 1 tablespoon of the mixture (per cookie) onto a plate or baking sheet lined with parchment paper or plastic wrap. Gently flatten and shape each cookie. Cover with plastic wrap and refrigerate for at least 30 minutes, preferably a few hours.

Eat chilled. Store in the refrigerator for up to 2-3 days.