Preheat your oven to 180°C (160°C fan) and line two baking trays with parchment paper. The paper should feel taut and smooth against the tray — no wrinkles, or your cookies will spread unevenly.

In a large bowl, beat the softened butter with both sugars until the mixture looks pale and fluffy. You'll see the colour lighten from yellow to a soft cream, and the texture becomes airy and light. This takes about 2 minutes with an electric mixer or 3 minutes by hand.

Crack in the egg and add the vanilla extract, then beat again until fully combined. The mixture should look glossy and smooth, with no streaks of egg visible. You'll smell the vanilla as soon as it hits the butter.

In a separate small bowl, whisk together the flour, bicarbonate of soda, and salt. This ensures the raising agent is evenly distributed — if you skip this, you might get a cookie that's puffy in one spot and flat in another. The flour mixture should feel light and powdery when you stir it.

Add the dry ingredients to the wet mixture in two additions, stirring gently with a wooden spoon or spatula until just combined. Stop as soon as you no longer see white streaks of flour. The dough should be soft and slightly sticky, but not wet. If it feels greasy, you've overmixed.

Fold in the chocolate chips until they're evenly scattered through the dough. You should see chocolate in every spoonful. The dough will now look speckled and feel studded with chocolate pieces.

Scoop tablespoon-sized balls of dough (about 25g each) onto the prepared baking trays, leaving at least 5cm between each one. They should be roughly round, but don't worry about perfection — the oven will sort them out. You'll have about 12 cookies per tray.

Bake for 8–10 minutes, or until the edges are golden brown and the centres still look slightly pale and soft. The kitchen should smell warm and sweet, like caramel and vanilla. The tops will be set but will feel soft to a light touch. Don't wait for the centres to turn brown — they'll continue cooking as they cool.

Remove from the oven and let the cookies rest on the tray for 5 minutes. During this time, they'll firm up and the chocolate will set slightly. You'll see the edges become crisp and the middles settle into a chewy texture.

Transfer to a wire cooling rack to cool completely, or serve warm if you can't wait. The cookies should lift cleanly off the parchment paper without sticking. If they crumble, they needed a minute more on the tray.