Combine melted butter and semolina and set aside at room temperature for 6 hours. Pulse the pistachio with the sugar and rose water until finely ground but do not over process as the nuts will become oily. Add the pistachio mix to the semolina and mix well. Divide the mixture in half and shape into 2 × 26 cm rounds, on a tray lined with waxed paper. Chill until firm.
To prepare the kashta, combine the NESTLÉ® Sweetened Condensed Milk , water and corn flour in a saucepan. Bring to boil, stirring constantly, and cook until thick. Remove from heat and add the flavoured water, to taste. Cover the surface with plastic wrap and set aside to cool completely.
To assemble the recipe, line a 26cm spring form tin with plastic wrap, crossing at right angles and hanging down the sides. Place one of the pistachio and semolina rounds in the base of the tin, spoon over the cooled kashta and top with the remaining round. Refrigerate for 4 hours before serving, dusted with icing sugar.