Preheat oven to 180°C degrees.
Whisk the egg whites into fluffy meringue and add one egg yolk.
Add the sugar, flour, baking powder, semolina and lemon rind.
Bake for about 45 minutes in a low rectangular baking tin.
Leave to cool and prepare syrup.
Bring the water to boil with the sugar, vanilla and lemon juice.
Cut into pieces while still in the baking tin and pour the syrup over after it has cool to room temperature.