Prep the air fryer: Preheat to 330°F (165°C) for 3–5 minutes. Line the basket with a parchment liner or lightly spray to prevent sticking.

Cream the fats and sugars: In a medium bowl, beat the butter, peanut butter, granulated sugar, and brown sugar until smooth and fluffy, about 1–2 minutes.

Add wet ingredients: Beat in the egg and vanilla until fully combined and glossy.

Combine dry ingredients: In a separate bowl, whisk the flour, baking soda, and salt. Add to the wet mixture and mix just until no dry streaks remain. If using add-ins, fold them in now.

Chill briefly (optional but helpful): If the dough feels soft or sticky, refrigerate it for 15–20 minutes. This helps hold shape in the air fryer.

Portion the dough: Scoop into 1 to 1.5 tablespoon balls. For classic look and texture, roll each ball in a little granulated sugar.

Crisscross: Place dough balls in the lined basket, leaving at least 1.5 inches between them. Gently press with a fork in a crisscross pattern to flatten to about 1/2 inch thick.

Air fry: Cook at 330°F (165°C) for 6–8 minutes, until edges are set and lightly golden. The centers may look slightly underdone—that’s good.

Cool in basket: Let cookies rest in the basket for 3–4 minutes to firm up. Transfer to a wire rack to cool completely.

Repeat: Continue with remaining dough, working in batches so cookies have room to spread and bake evenly.