Preheat the oven to 180˚C, gas mark 4.
Cream the butter and sugar until light and fluffy – for approximately 8 minutes.
Sift together the cornstarch and flour and add to the butter mixture to form a soft dough. Mix in the orange blossom water.
Roll out the dough ½ cm thick on a lightly floured surface, then cut shapes using a round cookie cutter just big enough for the size of the flowers. We used a 5cm cutter.
Place on a lined baking sheet and refrigerate for 30 minutes or until firm.
Bake in the preheated oven for 10-15 minutes or until golden around the edges.
Meanwhile, gently wash the flowers in cool water and drain well. Place the flowers stem side up on clean paper towels for about 15 minutes to dry. Using scissors, cut the stems off. Be careful not to cut too far down so the flower won’t break apart. Turn the flowers over to finish drying.
In a small bowl, whisk the egg white and 1 tablespoon of water until well blended. Lightly brush the tops of each cookie with the egg mixture. Place 1 flower on each cookie, gently press it into the dough using a rolling pin and lightly brush the flowers all over with the egg wash. Sprinkle the cookies with caster sugar and return to the baking sheets.
Bake the cookies for an additional 5 minutes, or until the flowers have dried onto the cookies. Transfer the cookies to a cooling rack.