For the gnocchi: Place a large pot on the stove and bring to a boil. Once the water is boiling add the potatoes and cover with a lid. Leave boiling for 20 minutes.
Take a potato from the pot, hold in a tea towel and squeeze to test how soft it is. When you can easily make a dent in the potato it is ready. Remove the potatoes from the water. It is better for them to be overdone than underdone.
Peel the potatoes one by one and place them in a large flat dish. You can use a potato press or fork to mash the potatoes until there are no lumps left.
Add the egg, oil, Parmigiano, seaweed and flour into the potato dish and mix it together with your hands. If you have rice flour or potato starch to cover your hands with, it is much easier to mix and roll the gnocchi.
Put a large pot on the stove to boil.
Make the mixture into one ball and separate into four balls. Roll each ball into long thin strips that are roughly 1 – 2 cm in diameter. Cut the mixture in 2 cm intervals and roll each one on your hands until they are smooth spheres. Do this with all of the mixture.
When the water is boiling place a handful of gnocchi in the water at a time. Make sure you don’t put too much, the gnocchi should not touch in the water. When the gnocchi begins to float they are ready to take out, this should take 30 seconds to a minute. Place the finished gnocchi in a bowl.
Repeat with all of the gnocchi.
Dice onion and garlic.
Take a frying pan and heat the butter until melted. Add the onion and cook until golden, then add garlic.
Make sure the pan is hot enough by dropping one piece of dry nori in first. If it bubbles at the edges and changes colour it is hot enough. Add the rest of the dry nori to the pan.
When the nori has turned a dark green colour add your gnocchi to the pan and bring the heat down to medium. Fry the gnocchi in the pan until they become brown and slightly crispy.
Serve with grated parmesan and black pepper to taste.