Pour cold water over the dried wakame seaweed and leave to soak for 10 minutes.
Bring 300ml of water to the boil, then add OFJ dashi powder. Next add the hon-tsuyu and carefully adjust to taste. Generally you will want a ratio of 1 cup of hon-tsuyu to 2 cups of water, depending on concentration and brand.
When the broth comes to the boil, add the pre-cooked udon noodles and simmer for 10 minutes.
Your noodles should now be ready to eat, so transfer them to a bowl with some of the soup. Garnish with the drained wakame seaweed, a slice of kamaboko fish cake, spring onions, and a sprinkle of bonito flakes, and shichimi chilli powder if you're adventurous.