Croissant Dough& Croissants

• 4 1/2 sticks butter (unsalted)
• 1 recipe croissant dough well (chilled)
• 1 flour for rolling dough
• 1 egg
• 450 gr flour
• 240 ml milk
• 65 gr sugar
• 28 gr yeast (fresh)
• 16 gr flour
• 6 gr salt