Step 1

In a large pot, add a piece of kombu (seaweed).

Step 2

Cover with 4 C water.

Step 3

Bring the water up to a simmer. (Don't boil the kombu or it will become slimy). Skim off any foam.

Step 4

Remove the kombu.

Step 5

Add in the bonito flakes. Bring it up to a simmer again, for about 30 seconds before turning off the heat.

Step 6

Let the broth sit for 10 minutes before straining the liquid through a sieve.

Step 7

You can discard the bonito flakes or make furikake with it.

Step 8

Transfer the broth to a glass jar and let cool. Place into the fridge until ready to use.

Step 9

Transfer the prepared dashi broth to a pot and heat to a simmer.

Step 10

Keep the soup warm while preparing the rest of the ingredients.

Step 11

Transfer the prepared dashi broth to a pot and heat to a simmer.

Step 12

Add in soy sauce and mirin and bring it to a boil.

Step 13

Give it a taste and adjust accordingly with salt.

Step 14

Using a small saucepot (I used 1.5qt), add 800ml of water to it. (Be sure that the eggs can sit in the pot fully submerged).

Step 15

Bring the water to a hard rolling boil. Once boiling, remove from heat and add 250ml of cold water into the pot.

Step 16

Gently place 4 eggs (straight from the refrigerator) into the hot water. (You may want to use a slotted spoon to do this).

Step 17

Set a timer for 15 minutes.

Step 18

Remove the eggs from the pot. Set aside until ready to use.

Step 19

Heat up 1 Tbsp vegetable oil in a large frying pan over medium-high heat.

Step 20

Add in the beef slices and cook, until no longer pink.

Step 21

Season with soy sauce, sugar, and garlic powder.

Step 22

Transfer to a plate and cover.

Step 23

Bring a large pot of water up to a boil.

Step 24

Cook the udon noodles according to the package instructions.

Step 25

Drain the udon noodles in a colander and gently rinse under cold water. Set aside.

Step 26

Portion the udon noodles into a serving bowl.

Step 27

Ladle the hot soup broth over the noodles.

Step 28

Add the cooked beef and crack in an onsen egg.

Step 29

Garnish with green onions and togarashi spice (optional).

Step 30

Enjoy immediately.