In a small pot, add dashi and bring it to boil over medium heat.
Cook the sliced pork one at a time in the dashi. Try not to overcook as it gets tough. Once the pork is no longer pink, quickly remove it from the dashi.
Place the cooked pork in iced water. Once cooled, transfer to a plate.
Skim off fat and foam on the surface of dashi.
Add the curry roux cube in a ladle and let it dissolved completely in the ladle. If you drop the curry roux cube in the dashi, it’s much harder to dissolve.
Add 1 Tbsp sake and 3 Tbsp mirin.
Add 2 Tbsp soy sauce and mix together. Bring the sauce to a simmer.
Skim off foam and cook for 1 minute. Let cool in an ice bath. Once it’s cool, you can move to the refrigerator.
Cut the eggplant into 4 wedges lengthwise. Heat the oil in the pan. I use a cast iron grill pan to get the grill mark.
Cook all sides of eggplant until tender.
Slice the onion thinly. I use the mandolin slicer to get thin onions. Soak in iced water to remove bitterness.
Peel the cucumber skin alternatively. Slice the cucumber and cut into julienne strips.
Cut the tomato into wedges. Cut the mizuna into small pieces.
Pour the curry soup into serving bowls. You can remove fat on the surface of the curry soup with a fine mesh skimmer or strain the curry soup through a fine mesh sieve.
Bring a large pot of water to boil for udon noodles. My favorite udon is the frozen Sanuki Udon. Cook the frozen udon noodles in boiling water for 1 minute (no need to defrost). If you use dry noodles, follow the package instructions. Drain and run under cold water to chill the udon.
Place the udon in the curry soup and add toppings (boiled egg, pork, eggplant, onion, cucumber tomato, and mizuna) on the top.
You can keep the soup and toppings in airtight containers separately, but I recommend preparing udon noodles right before you serve. Store in the refrigerator for 3 days and in the freezer for a month.