Beat the eggs with the sugar until thick. Add semolina, milk and flavouring. Cook over a low heat until mixture thickens stirring continuously. Remove from heat. Add 3 tablespoons butter. Butter a baking pan 9 X 12 X 2 inches and spread 2/3 of pastry sheets, brushing each sheet with melted butter. The edges of the pastry sheets should exceed the top of the pan. Spread milk mixture over the pastry sheets and turn in the edges of the sheets over the cream. Cover with remaining pastry sheets, brushing each with melted butter. Pour any remaining butter over top. Cut through the first 3 sheets in 3-inch squares and sprinkle with water. Bake in a moderate oven for 45 minutes.
Syrup preparation : Boil sugar, water and lemon juice for 5 minutes. Pour lukewarm syrup over the ghalactoboureko. Allow cooling before serving.