For the sugared rose petals, carefully peel off rose petals, then brush lightly with egg white. Sprinkle with sugar and shake off excess. Place on a rack and set aside for 2-3 hours to dry.
Preheat oven to 180C. Beat egg whites in a clean, dry bowl until soft peaks form. Beat in the cream of tartar until just combined. Gradually add 155g of the sugar, in batches, beating well after each addition. Sift flour and remaining sugar together then gently fold flour mixture and a little food colouring into egg white mixture.
Cut a circle of non-stick baking paper and line the bottom of the angel food cake pan then spread mixture into the ungreased angel food cake pan. Smooth the surface and wipe side of pan clean. Bake for 20-25 minutes or until the mixture springs back slightly when touched.
Immediately invert the pan onto a wire rack and allow the cake to cool completely in the pan. Once cool, gently run a palette knife around both sides of the pan to loosen cake. Gently ease the cake out of the pan. Place upside down on serving plate.
Combine the icing sugar, water and rosewater in a bowl and tint pink with food colouring. Drizzle icing over top of cake, allowing icing to drip down the side and decorate with sugared rose petals and freeze dried raspberries.
