Cream the Butter and Sugars: In the bowl of a stand mixer fitted with the paddle attachment, beat the softened butter, caster sugar, and brown sugar on medium speed until pale, light, and fluffy. You should see the mixture increase in volume, and it will smell sweet and buttery. This takes about 3 minutes.

Add the Wet Ingredients: Beat in the egg, vanilla extract, and molasses. The mixture will look a little curdled and glossy at this point – that’s perfectly fine. Scrape down the sides of the bowl with a silicone spatula.

Combine the Dry Ingredients: In a separate bowl, whisk together the plain flour, bicarbonate of soda, cinnamon, nutmeg, and sea salt. The flour will smell earthy and aromatic.

Incorporate the Dry into the Wet: With the mixer on low speed, gradually add the flour mixture. Mix just until the last streaks of flour disappear. The dough will be very thick and slightly sticky. Do not overmix, or the cookies will be tough.

Fold in the Oats and Raisins: Switch to a silicone spatula. Gently fold in the rolled oats and the drained raisins. The dough will become stiff and chunky, with the oats and raisins evenly distributed. You’ll feel the resistance of the oats against the spatula.

Chill the Dough: Cover the bowl tightly with cling film and refrigerate for at least 1 hour, or up to 24 hours. This is non-negotiable for a chewy texture. The dough will feel firm and cold to the touch.

Preheat and Prepare: Preheat your oven to 180°C (160°C fan) and line two large baking trays with parchment paper. The paper should be taut and flat.

Portion and Shape: Scoop out 40g portions of dough (about a heaped tablespoon). Roll each portion into a smooth ball between your palms. Place them 7-8cm apart on the prepared trays. Do not flatten them; they will spread naturally in the oven.

Bake to Perfection: Bake for 12-14 minutes, rotating the trays halfway through. The cookies are ready when the edges are a deep golden brown and set, but the centres still look slightly underdone, puffy, and soft. The smell of toasting oats and cinnamon will fill your kitchen.

Cool and Set: Let the cookies rest on the hot baking tray for exactly 5 minutes. This is crucial for a chewy centre. You will see them settle and the tops crack slightly. Then, transfer them to a wire cooling rack to cool completely.