Preheat the oven to 180°C.
Beat the butter and sugar in a bowl until pale and fluffy.
Dredge blueberries in flour, then remove and set them aside.
Mix the flour and ground almonds into the butter mixture.
Add the rosewater and blueberries and combine.
Gently fold in the stiffened egg whites.
Spoon the mixture into a muffin tin lined with cupcake cases.
Bake for 12 to 15 minutes until risen and golden-brown.
Cool the cupcakes on a wire rack.
Mix icing sugar, food colouring, lemon juice, water, and rosewater in a clean bowl.
Spread the icing onto the cooled cakes and smooth with a hot knife.
Decorate with rose sweets or petals before serving.