2In a mixing bowl, combine the mashed Gongju chestnuts, 40 grams of granulated sugar, 20 grams of unsalted butter, 30 grams of whole milk, and 1 gram of salt. Mix well until a smooth, cohesive chestnut filling is formed. Divide the chestnut filling into 8 equal portions, approximately 30-35 grams each, and roll them into balls.
3In a large mixing bowl, combine the strong bread flour, 30 grams of granulated sugar, 5 grams of active dry yeast, and 3 grams of salt. Mix these dry ingredients thoroughly.