• Preheat the oven to 320°F (160°C) or 300°F (150°C) for convection ovens.
• Grease and line a 9 inch (23 cm) square pan with parchment paper, leaving some overhang on the sides.
• Beat the butter until smooth, then sift in the powdered sugar and beat together for 2–3 minutes, until pale and creamy.
• Add the flour: Sift in the flour and gently mix with a spatula or your hands until a soft dough forms. Do not overmix.
• Press the dough evenly into the prepared pan. Gently mark the portions without cutting through the dough, then pierce with a fork.
• Bake: Bake for 25–30 minutes, until lightly golden on top.
• Cut while warm: Remove from the oven and lift out using the parchment paper. Cut fully along the marked lines while the shortbread is still warm.

Storage

• Room temperature: Store in an airtight container for up to 7 days.
• Refrigerator: Keeps well for up to 10 days in an airtight container.
• Freezer: Freeze in an airtight container, layered with baking paper, for up to 3 months. Thaw at room temperature before serving.