Measure flour into a bowl and mix in water with a fork or chopsticks. Work dough several minutes until it holds together, then knead on a lightly floured board until smooth and satiny (about ten minutes). Cover and let rest at room temperature for 30 minutes. Roll dough into a 30 cm long log. Cut into dozen equal pieces and keep covered. To make each pancake, cut one piece of dough exactly in half. Roll each half into a ball and flatten slightly. Roll each ball on a very lightly floured board to a round 8 cm in diameter. Brush sesame oil lightly on top of one round and cover with another round. Press the 2 rounds lightly but firmly together. Place the double round on a lightly floured board and roll out, from center to edges, until 7 or 20 cm in diameter (don't worry if rounds are not perfect). Turn frequently, brushing board lightly with flour as needed. Repeat procedure until you have 2 or 3 pancakes; then cook before making more.

Heat a wide frying pan over medium-high heat, then place a pancake on the ungreased surface. Turn about every 15 seconds until cake is blistered by air pockets, turns parchment color and feels dry. Cake should not brown, but a few golden spots won't hurt. If overcooked, cake becomes brittle. Remove from pan and carefully pull the two halves apart and stack them on a plate. Keep covered as you cook remaining cakes. Serve warm; or let cool, wrap airtight, and refrigerate of freeze for later use. To heat for serving, thaw if frozen. Line a flat-bottomed steamer with towel dipped in water and wrung dry; stack pancakes inside and fold towel over pancakes. Cover and steam over simmering water for five minutes. Fold hot pancakes in half, then in half again, and arrange in a serving basket. Since they dry out quickly, serve just a few at a time and keep remainder covered.