Angel Cake:
Sift the flour, cornstarch, and half of the sugar (3/4 cup – 150g) three times.
Put the egg whites in a large bowl; sprinkle with salt and cream of tartar.
Beat the egg whites until stiff but not dry
Add the remaining sugar and vanilla while beating.
Continue beating until the egg whites form peaks, without being dry.
Gently fold in the sifted flour, 2 tablespoons at a time.
Pour carefully into a 10″ (25cm) ungreased tube mold.

Bake in a preheated oven at 300F (150C) for 50 minutes or until the top springs back when touched with a finger.
Invert the mold, suspend it over the neck of a bottle, to avoid the weight of the cake resting on the top crust.
Let cool completely.
Loosen from the sides with a flat knife or spatula and unmold.

Lemon Filling:
In a saucepan, mix all the ingredients and bring to a boil, over medium heat, stirring constantly with a whisk, until thickened.

Remove from heat and let cool.
Cover and refrigerate for about 2 hours or until the filling is completely cooled.

Italian Meringue:
In a saucepan, bring the water and sugar to a boil until the candy thermometer indicates 235F (113C). Remove from heat while beating the egg whites.

In a bowl, beat the egg whites, cream of tartar, and vanilla with an electric mixer until soft peaks form.
Pour the syrup over the egg whites while beating continuously until the meringue is warm and forms firm peaks.

Assembly:
Cut the cake horizontally to obtain 3 slices.
Spread half of the lemon filling between each layer.
Cover the top of the cake with the meringue (which you can brown under the grill if desired).
Keep the cake refrigerated.