Lemon soufflé tart

BASE: Sift flour, salt and sugar into a mixing bowl. Cut butter into small pieces and work into flour until small crumbs form.
Sprinkle with a little iced water (the less you use, the better your pastry will be), or use a food processor fitted with a steel blade. Process until pastry begins to form a ball. Gather pastry into a ball, drawing in any pastry sticking to sides of bowl. Pastry should be moist but not sticky
Wrap in waxed paper.
Chill for 1 hour before using. Press two thirds of pastry into base of a 25 cm or 28 cm diameter fluted loose-based tart pan, and press remainder into sides, making sure you cover fluted sections properly. Prick base and sides of pastry with a fork.
Bake at 180 ºC for 12 to 15 minutes, or until crust is a delicate golden brown. Remove from oven.
FILLING: Beat egg yolks with 125 g sugar until thick and creamy. Whisk in lemon peel and juice
Place in top of a double boiler and cook over medium heat until mixture coats back of spoon, stirring constantly. Do not allow to boil. Remove skin that forms on top with waxed paper and cool. (At this point, mixture may be refrigerated and tart completed at a later stage.)
Whisk egg whites with cream of tartar until stiff peaks form. Gradually add 45 g sugar. Using a slotted metal spoon, gently stir a quarter of whites into egg yolk mixture, then carefully fold in remainder. Do not overmix.
Spoon into baked pastry shell, mounding mixture up slightly at centre. Bake at 180 ºC for 12 to 15 minutes, or until top is golden. Switch off oven, open door and leave tart in oven to cool.
Sift a little icing sugar over just before serving or glaze top lightly with smooth apricot jam blended with a little lemon juice.