THE PLAIN GENIUS OF MENCHI KATSU SANDO

Ingredients

PRUNE KATSU SAUCE:
• 1/4 cup finely minced onions
• 1/4 tsp salt
• 1 tsp olive oil
• 8~9 (85 grams) pitted prunes
• 1 clove garlic, peeled
• 1/4 cup +2 tbsp (90 grams) water
• 1/4 cup (60 grams) balsamic vinegar
• 1/4 cup (60 grams) mirin/Japanese sweet rice wine
• 3 tbsp (51 grams) tomato paste
• 3 tbsp (45 grams) soy sauce
• 2 tbsp (32 grams) yellow mustard
• 1 tbsp (15 grams) worchestire sauce
• 2 tsp light brown sugar
• 1 tsp apple cider vinegar
• 1/4 + 1/8 tsp ground allspice
• a pinch of ground clove and ground cumin
MECHI KATSU/FRIED MINCED PORK PATTY: (makes 2 patties)
• 16 oz (460 grams) ground pork, preferably 30~35% fat
• 1/3 cup (50 grams) finely minced onion
• 2 tsp cornstarch
• 3/4 tsp sea salt
• 1/8 tsp ground white pepper
• 1 cup all-purpose flour
• 2 large eggs, beaten
• 2 cups Japanese panko breadcrumbs
• enough canola oil for frying
FOR THE SANDWICH:
• 4 slices of white bread
• 6~8 pitted prunes
• Dijon mustard

Instructions

1. PRUNE KATSU SAUCE: In a sauce pot over medium-low heat, cook minced onions with salt and olive oil, stirring often, until the onions are dark brown, caramelized and soft. Transfer the onions into a blender, along with all of the rest of the ingredients, then blend for 1 minute until smoothly pureed. Transfer back into the pot and simmer over medium-low heat (cover partially with lid to avoid splatters), stirring often, until it has reduced slightly, about 15 min. Can be made several days in advance and kept in the fridge.
2. PREPARE MENCHI KATSU: Gently and evenly mix ground pork, finely minced onion, cornstarch, sea salt and ground white pepper together. Divide into 2 equal balls, and throw it back and forth your palms to force out any air pockets inside, then place on a piece of parchment. Form into two square patties the same size as the sliced white bread, and flash-freeze for 30 min to firm up.
3. Place the all-purpose flour, beaten eggs, and panko breadcrumbs in three separate large containers. Season each slightly with salt and white pepper. Drench one patty in the flour, making sure it's evenly covered on every sides, then coat it evenly with beaten egg, making sure the egg is sticking to every nooks and crannies of the patty, then place the patty over the breadcrumbs. Use your hands to gently scoop the breadcrumbs over the patty to cover all surfaces, then turn the patty over and repeat, until it's completely covered and breaded. Repeat with the other patty. Leave them inside the breadcrumbs for at least 10 min for the coating to hydrate, while you heat up the oil.
4. TO FRY AND ASSEMBLE THE SANDWICH: Add enough canola oil in a frying pot until it reaches 2"/5 cm deep. Heat over medium-high heat until it bubbles up immediately and enthusiastically around an inserted wooden chopstick. Gently lower one breaded patty (do one at a time pls) into the hot oil, then lower the heat down to medium-low. Fry until golden browned on all sides, then transfer over a cooling rack to drain. Repeat with the other patty.
5. Let the patty cool for 10 min. Meanwhile, place pitted prunes in between 2 parchments, then with a meat-pounder, pound them until they're flattened out and broken. Trim off the sides of the white breads. On both sides of the sandwich, apply a generous smear of the katsu sauce. Then on one side, place 3~4 flattened prunes, and on the other, a little smear of Dijon mustard. Place the patty in between, then cut into 3 equal chunks. Serve immediately.