Put 8 cups flour into a large mixer bowl. Make a well in the center.

Add remaining dough ingredients into the well (excluding the remaining flour). Start mixing and slowly add the rest of the flour, 1 cup at a time. Dough should be soft and should not stick to the sides of the bowl.

Divide dough into 12 equal parts. Roll out each part into a very thin rectangular shape, taking care not to tear it.

Smear apricot jam generously onto each rectangle of dough. (Sprinkle on the lemon rind now, if using.)

Combine the nuts with the sugar, and sprinkle on top of all 12 rectangles of dough. Roll each rectangle up as tightly as possible, in jelly roll fashion.

Place rolls on a cookie sheet. Make slits down the top of each roll, every 2 inches. Brush with beaten egg.

Bake at 350°F for 1 hour.