In a large bowl, combine the flour, salt, sugar, and five spice powder (if using). Add ¾ cup water and mix to form a dough. Knead the mixture for about 5 minutes, until it forms a smooth ball. Set the dough aside and cover with a damp cloth. Let it rest for about an hour. In a small bowl, add the soy sauce, water, sugar, and a few chopped scallions and sesame seeds to make the dipping sauce. You can also add the garlic if using.
After the dough has rested, cut the dough in half and leave the other half under the damp cloth. Roll out the dough into a big rectangle, as thin as you can get it. Rub about half a tablespoon of oil all over the surface of the dough and sprinkle with half of the scallions, salt, and sesame seeds (if using). Cut 2 slits on each long side of the dough.
With the rolled out dough oriented vertically, start at the bottom and fold the two side flaps of dough over the middle piece. Then fold that entire rectangle forward onto the middle level. Fold those to flaps over, and repeat.
When you have your nice, neat rectangle, take your rolling pin and roll it until almost doubled in area. Take care not to roll too firmly, as you don’t want the dough layers to bind and you want to keep some small pockets of air between them.
Heat a couple tablespoons of oil in a pan over medium heat and add the pancake. Cover the pan and cook for about five minutes on each side, or until golden brown. Transfer to a cutting board, slice, and serve with your dipping sauce. Repeat the process with the other half of the dough and scallion mixture.
Note: To freeze, place a layer of waxed paper, parchment paper, or plastic wrap between each pancake and store in an airtight ziploc bag.