In a mixer, beat the eggs well. Add in sugar and oil, and beat together thoroughly. Add potato starch, salt and orange zest to the egg mixture. Then start pouring a little cake meal, alternating with the 1/4 cup of orange juice. Continue alternating, pouring in juice and cake meal (about 3/4-1 box all together, depending on size of eggs). If adding nuts, add them at the point at which the dough starts to firm up, but is not too firm to incorporate the nuts. Add cake meal until batter begins "climbing up" the beaters of the mixer -- it should feel firm. TIP: Place dough in refrigerator to make it easier to work with. Once dough has chilled, remove.
Preheat oven to 375. Grease 2 cookie sheets with cooking spray and set aside. Dust counter with cake meal and break off a fistful of dough. Gently roll each piece into a long rope about 1-1 1/2 inches thick and about 1/2-3/4 the length of a cookie sheet. Then gently lay each rope on prepared sheet, and as you straighten it, stretch it gently to about the length of the sheet. About 4 ropes should fit on a single sheet. You should have about 6-8 ropes in all. Brush ropes with remaining orange juice and then sprinkle with cinnamon and sugar.
Place pans in preheated oven and bake for 20 minutes. Remove from oven, slice ropes about 1/2 inch wide on an angle, and turn them on their sides. Sprinkle again with cinnamon and sugar, and return to oven for another 20 minutes. They should look very golden brown.
SPECIAL TIP: Turn off oven. Since the mandel bread tends to be soft if you take it out of the oven too soon, it's best to make them at night, and then leave in the oven overnight to dry out. Enjoy!