After the last drain, combine acorn meal with 5 cups of water in a large pot. Bring to a rolling boil, then reduce heat to a low boil. Keep stirring to prevent acorn meal from burning. Whisk cornstarch and salt with 3 tablespoons water until smooth. Add to pot. Continue stirring until volume is reduced by half and liquid is thickened, about 30 minutes.
03Coat four small serving bowls with vegetable oil. Strain acorn mixture through a fine-meshed sieve and divide among the bowls. Allow to rest at room temperature until set, about 2 hours.04For the dressing: In a small bowl, whisk together soy sauce, vinegar, sesame oil, pepper flakes, sesame seeds and garlic. Add scallion, and mix.05For the dressing: To serve, invert a bowl of jelly onto a serving plate, and remove bowl. Top with a spoonful of dressing. Repeat with remaining jelly and dressing, and serve.