• Gather all the ingredients.
  

To Prepare the Ingredients

• Soak dried shiitake mushrooms in water to rehydrate for 15 minutes. You need just enough water to cover the mushrooms and place a smaller bowl on top to keep the mushrooms submerged in water.
  
  
• Squeeze the excess water out of rehydrated shiitake mushrooms. Cut off the stems if there are any and score a cross on top like this and set aside (use it later for topping). Reserve the leftover soaking liquid (shiitake dashi) for udon soup by straining it through a mesh strainer to remove any grit or impurities before using it.
  
• In lightly salted boiling water, blanch the spinach starting from the stem side for 1 minute.
  
• Soak the spinach in iced water to prevent overcooking. Squeeze water out and cut into 1 ½” (4 cm) pieces.
  
  
• Slice the carrot. Optionally you can cut out the carrot into a flower shape with a vegetable cutter.
  
• Cut kamaboko into thin slices and break shimeji mushrooms into small pieces.
  
  
• Slice the long green onion diagonally and cut the chicken into 1” (2.5 cm) pieces.
  
  

To Make the Udon Soup

• To make udon soup, combine the dashi and shiitake dashi (reserved liquid from dried shiitake mushrooms) in a small saucepan. Bring it to a boil over medium-high heat.
  
• Once boiling, add mirin, soy sauce, and salt. When boiling again, turn off the heat and set aside.
  
  

To Make Shrimp Tempura

• To make shrimp tempura, follow this instruction to clean the shrimp and make them straight.
  
• To make the tempura batter, combine the tempura batter mix and water. Lightly dust the shrimp with potato starch/cornstarch before dredging the shrimp in the batter. Deep fry at 340-350 ºF (170-180 ºC) until golden brown. If you want to make the tempura batter from scratch and learn tips on how to deep fry the shrimp, you can read the recipe here.
  

To Prepare Udon Noodles

• 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 30 seconds (no need to defrost). If you use dry noodles, follow the package instructions. Drain the water and chill in ice water to prevent the noodles from cooking further.
  

To Assemble

• Divide all the ingredients (except for the egg, spinach, and mitsuba) into two individual earthen donabe clay pots (or use any big pot).
  
• Add udon soup and cover with the lid. Bring the soup to a boil over medium-high heat. When it comes to a boil, leave the lid slightly open to let some steam out, or it will overflow. Lower the heat and simmer to cook until the chicken is cooked through.
  
  
• Add an egg, spinach, and mitsuba and cover to cook until the egg is done to your liking.
  
  
• Add shrimp tempura on top and serve. Sprinkle shichimi togarashi (Japanese seven spice) if you like the soup spicy.
  
  

To Store

• You can keep the noodle soup and toppings separately in airtight containers and store in the refrigerator for up to 3 days. You have to prepare udon noodles right before you serve.