Lay down a piece of parchment paper. Use rolling pin to roll loaf into a 12x16-inch rectangle. Cover with plastic wrap and let rest for 10-15 minutes.
Cook spaghetti according to instructions. Remove wrap from dough.
Place spaghetti lengthwise in a 4-inch strip down the center of the dough. Tip with sauce and cheese cubes. You may add 1/2 pound sausage.
Make cuts 1 1/2-inches apart on long sides of dough to within 1/2-inch of filling. Then braid strips left over right, right over left.
Finish by pulling last strip over and tucking under braid. Lift braid with both hands and place on large sprayed baking sheet. Brush with egg white and sprinkle Parmesan cheese and parsley. I added garlic powder.
Bake at 350º for 30-35 minutes or until golden brown.