For the Shokupan:
In a pot over medium heat, stir together 185 grams milk and 50 grams bread flour to create a loose roux. In a stand mixer fitted with a dough hook attachment, add yeast, sugar, salt, and remaining bread flour. With the mixer running on low, add the roux, eggs, and remaining milk. Continue mixing on low for 5 minutes. Add butter and continue to mix an additional 10 minutes. Let dough proof 30 minutes. Heat oven to 375°F. Place dough on a lightly floured work surface. Using a rolling pin, roll dough into a rectangle. Using your hands, roll the rectangle into a log the length of your pullman loaf pan then place in the loaf pan. Proof 45 minutes. Bake 30 minutes. Remove shokupan from loaf pan and let cool completely.
For the Chicken Katsu:
In a stock pot, combine mirin, brown sugar, ginger, scallion, peppercorns, and garlic and bring to a simmer. Continue simmering 15 minutes. Add tamari and 2 kilograms water. Return to a simmer. Remove from heat and cool completely. Add chicken breasts, cover, and refrigerate 12 hours (or overnight). Heat a deep fryer to 335°F. Remove chicken from brine and pat dry. Dredge chicken in flour, followed by egg, then panko. Fry until golden. Set aside.
For the Curry:
Heat oven to 375°F. Rub squash with oil. Roast 45 minutes. Scoop out the flesh then mash until no chunks remain. Set aside. In a large pot over medium flame, heat enough oil to generously coat the bottom. Add onion, carrot, and potato. Cook until soft. Add curry powder and garam masala and continue to cook 5 minutes. Add tamari, brown sugar, and chicken stock or at least 1 kilogram water to loosen the mixture. Add the mashed kabocha and stir until vegetables are fully cooked and thickened, making sure the bottom doesn’t scorch. Reserve.
To Assemble and Serve:
Spread mayonnaise onto 2 slices Shokupan. Layer 1 slice with 1 Chicken Katsu portion, 3 ounces Curry, pickled ginger, and scallion. Close sandwich and slice in half.
Created by Chefs Leina Horii and Brian Lea of Kisser, adapted by StarChefs.