In a food processor blitz the butter, flour and sugar until it resembles fine breadcrumbs.

Add in the vanilla essence and egg yolk, then process until combined.

Add your water to the processed mixture one tablespoon at a time. Blend the mixture after each addition. When the dough begins to form clumps it is ready and you have added in enough water.

Remove the dough from the food processor and use your hands to form it into a smooth ball.

Grease a deep pie dish (approx 22cm diameter) with a little bit of extra butter and lightly dust the surface with flour.

Roll your dough out evenly between 2 sheets of baking paper. The dough should be about 5mm thick and roughly 35 cm round.

Peel the pastry from the baking paper and lay it over the prepared pie dish. Press the pastry into the the dish and trim the edges. You can use the scraps of dough to create a decorative edge on your pie crust if you like.

Place your prepared pastry base in the fridge for half an hour to chill.

Preheat your oven to 170 degrees fan bake. Cover your pastry with a large piece of baking paper that has been crumpled, place pastry weights on top and par-bake your pastry for 12 minutes. When it is ready remove the pastry from the oven and carefully take out the baking paper and weights.

Increase your oven temperature to 180 degrees once the pastry is out.

While your pastry is par-baking you can prepare your lemon filling.

Dice the butter and place it into a small bowl along with the egg yolks and lemon juice. Set that aside.

In a medium sized saucepan mix together the sugar and cornflour before adding in the water.

Mix constantly over a medium heat until it the mixture thickens and the is almost translucent. This should take about 3-5 minutes.

Quickly mix through the lemon, butter and egg yolks. Continue heating and mixing until the butter is melted and it has thickened up again.

Pour your lemon filling over your pre-baked base while both are still warm. Spread the mixture evenly over your pastry base.

Whisk the egg whites and cream of tartar together until the mixture is foamy.

Begin to add in your sugar, sprinkling over a heaped tablespoon at a time.

Whisk your meringue constantly until all of the sugar is fully incorporated and stiff peaks have formed. The meringue will take up to 10 minutes to be fully whisked.

Use a large spoon to dollop spoonfuls of the meringue on top of your prepared pie. Spread the meringue over the surface evenly and use the back of a small spoon to create a simple zig-zag swirl on top.

Place into your 180 degrees preheated oven. Immediately turn the temperature down to 140 degrees. Bake for 25-30 minutes or until the meringue is golden and crisp. Turn the oven off and leave the pie in the oven for another 30 minutes to 1 hour. Remove your pie from the oven and allow it to cool before slicing.