Walnut Ghriba

Ingredients:

15.5 oz (450 grams) of raw walnuts
A few pebbles of arabic (mastic) gum (optional)
1/2 cup (100 grams) granulated white sugar
A pinch of salt
1/2 teaspoon ground cinnamon
1 tablespoon apricot jam (optional)
2 large eggs (egg yolks and egg whites separated)
1 teaspoon baking powder
1 tablespoon (15 grams) butter melted
Powdered sugar for rolling