In a bowl, mix flour, sugar and salt. Add cold butter. Rub it into the flour until it looks like crumbs. Add cold water slowly and form a soft dough.

Wrap the dough in cling film. Place it in the fridge for 20 minutes. This helps the pastry become crisp and easy to roll.

Roll the dough on a floured surface. Make a round shape to fit your pie dish. Gently place it in the dish and press edges.

Preheat oven to 180°C (350°F). Prick the base with a fork. Bake for 15 minutes until lightly golden. Let it cool slightly.

In a saucepan, mix sugar and cornstarch. Add water slowly while stirring. Cook on medium heat until it thickens.

Whisk egg yolks in a bowl. Slowly add hot mixture while stirring. This prevents eggs from scrambling. Return to heat and cook until smooth.

Add lemon juice, lemon zest and butter. Stir well until creamy. The filling should be thick and shiny. Remove from heat.

Pour the lemon filling into the baked pastry base. Spread it evenly. Let it sit while you prepare meringue.

In a clean bowl, beat egg whites until soft peaks form. Slowly add sugar while whisking. Continue until stiff and glossy peaks appear.

Spread meringue over the lemon filling. Make sure it covers completely. Use a spoon to create soft peaks on top.

Bake at 180°C (350°F) for 10–12 minutes. The top should turn light golden brown. Watch carefully to avoid burning.

Let it cool before slicing. This helps layers set properly. Serve chilled or at room temperature.