Start by measuring all your ingredients accurately. Make sure the butter is at room temperature so it mixes easily with the sugar and flour. This step ensures a smooth, even dough.
Combine butter, caster sugar, flour, and salt in a bowl or food processor. Pulse until the mixture resembles coarse breadcrumbs. Press together with your fingers to check if it forms a soft dough.
Press the dough into a greased baking pan using your fingers until it’s evenly spread. Use a fork to prick the top in rows, which helps it bake evenly and makes cutting easier.
Preheat the oven to 350°F (175°C). Bake the shortbread for 30–35 minutes until it’s light golden and firm to the touch. Sprinkle lightly with caster sugar as it cools.
Let the shortbread cool completely before cutting it into fingers, rounds, or triangles. Serve with tea, coffee, or simply enjoy as a buttery snack.