Stuffed semolina cookies (ma'amoul)

Dough

• 600 g butter, cut in pieces
• 20 g dried yeast
• 1000 g medium wheat semolina
• 500 g fine semolina
• 100 g sugar
• 6 mastic gum grains
• 14 mahleb seeds
• 150 g rose water
• 70 g blossom water
• 200 g water

Filling

• 550 g pistachio nuts, shelled, unsalted
  sau 550 g walnuts, shelled
• 30 g sugar
• 25 g blossom water
• 50 g rose water

Assembly

• 100 g icing sugar