Prepare Your Dry Ingredients: In a medium bowl, whisk together the plain flour, baking powder, bicarbonate of soda, and salt. Whisking helps to evenly distribute the leavening agents. Set this aside.

Cream Butter and Sugar: In the bowl of a stand mixer fitted with the paddle attachment, or in a large bowl using a hand mixer, beat the room-temperature butter and caster sugar on medium speed for about 3-4 minutes. You're looking for a light, pale, and fluffy texture. This step incorporates air, which is vital for a soft cookie. For more on this technique, BBC Good Food has a great guide.

Add Wet Ingredients: Add the egg and vanilla extract to the creamed butter and sugar. Beat on medium speed until just combined, scraping down the sides of the bowl once to ensure everything is incorporated.

Combine Wet and Dry: With the mixer on its lowest speed, gradually add the flour mixture to the wet ingredients. Mix only until the last streaks of flour have disappeared. Be careful not to overmix here, as that can develop the gluten and make the cookies tough.

Fold in the Strawberries: Remove the bowl from the mixer. Gently fold the diced strawberries into the dough using a spatula until they are evenly distributed. The dough will be quite soft at this point.

Chill the Dough: Cover the bowl with cling film and refrigerate for at least 30 minutes, or up to an hour. What works best for me is this minimum 30-minute chill, as it solidifies the butter and makes the dough much easier to handle. It's the most important step for preventing excess spread.

Scoop and Bake: Preheat your oven to 180°C (160°C Fan). Line two large baking trays with parchment paper. Use a medium cookie scoop or two spoons to drop rounded tablespoons of dough onto the prepared trays, leaving about 5cm of space between each one to allow for spreading.

Bake to Perfection: Bake for 12-15 minutes, or until the edges are lightly golden brown and the centres look set. They might appear slightly underdone in the very middle, but they will continue to cook on the hot tray.

Cool Completely: Let the cookies cool on the baking tray for 5 minutes before carefully transferring them to a wire rack to cool completely. They are delicate when warm.

Glaze and Enjoy: While the cookies are cooling, whisk together the sifted icing sugar, 2 tablespoons of milk, and the vanilla extract in a small bowl. Add more milk, a teaspoon at a time, until you reach a thick but pourable consistency. Drizzle the glaze over the completely cooled cookies. Allow the glaze to set for about 20 minutes before serving.