Maamoul Pistachio Walnut and Date Pastries

Name: Maamoul (Pistachio, Walnut, and Date Pastries)
Ingredients: 1 cup pistachios, chopped; 5 Tbsp. sugar; 1 Tbsp. rosewater; 1 Tbsp. orange blossom water; 1 cup walnuts, chopped medium fine; 2 Tbsp. orange blossom water; Zest of ½ an orange; 1 tsp. cinnamon; 2 cups chopped pitted dates; 1 Tbsp. ground nutmeg; 1 Tbsp. melted butter; 2 lb. (6 cups) fine semolina; 2 Tbsp. ground mahlab; 3 cups clarified butter, melted; 1 tsp. instant dry yeast; 1 Tbsp. sugar; 2 cups full-fat milk, lukewarm; Icing sugar, for dusting