Step 1: Cream Butter and Sugars: In a medium bowl, beat softened butter with brown sugar and granulated sugar until pale and fluffy — about 2 minutes by hand or 1 minute with a mixer. This step is what makes cookies tender. Breaking down the sugar crystals now prevents a gritty texture later.

Step 2: Add Egg and Vanilla: Beat in the egg and vanilla extract until fully blended and smooth. The egg emulsifies into the butter mixture, giving the dough richness and even texture.

Step 3: Fold in Dry Ingredients: Sift in flour, baking soda, and salt. Fold with a spatula just until no streaks of flour remain. Overmixing develops gluten and makes cookies tough and cakey — stop as soon as you don't see dry flour.

Step 4: Add Chocolate Chips: Pour in chocolate chips and fold until evenly distributed. Every scoop of dough should be studded with chips — the more even the distribution, the more consistent each bite.

Step 5: Air Fry: Scoop about 1 tablespoon of dough, roll into a ball, and flatten slightly onto a parchment-lined air fryer basket. Bake at 160°C (320°F) for 8–10 minutes until edges are golden. Air fryers run hot — keep the temperature on the lower side to avoid burning the edges before the center sets. Residual heat will finish cooking the middle as they rest.