Lemon meringue pie

Pastry

• 100 g unsalted butter, chilled, cut into pieces, plus extra for greasing
• 50 g icing sugar
• 230 g plain flour, plus extra for dusting
• 1 pinch salt, to taste
• 3 egg yolks

Filling

• 1 lemon, zest only, no white pith
• 100 g caster sugar
• 220 g lemon juice (approx. 6-7 lemons)
• 65 g unsalted butter, cut into pieces
• 6 eggs

Meringue

• 4 egg whites, room temperature
• ¼ tsp cream of tartar
• 150 g icing sugar