Add the 6 cups water and 1 tablespoon salt to a pot and bring it to a full boil. Next, add the 200 grams spaghetti and submerge it into the boiling water. Set the timer for 2 minutes less than what the package directions say.
6 cups water, 1 tablespoon salt, 200 grams spaghetti
While you wait for the water to boil, add the 200 grams shrimp, 7 grams garlic, and 1 teaspoon soy sauce to a bowl, and stir them together to coat the shrimp evenly.
200 grams shrimp, 7 grams garlic, 1 teaspoon soy sauce
When the pasta has about 5 minutes left on the timer, heat a frying pan over medium heat, add 1 tablespoon olive oil and shrimp, and spread them out in a single layer.
1 tablespoon olive oil
Fry the shrimp until they turn orange around the edges (about 30 seconds), then flip them over.
When no gray is left on the shrimp, transfer them to a clean bowl, and set them aside.
Add the 8 grams nori and ½ cup of boiling liquid from the pasta and stir until the nori has dissolved.
8 grams nori
If the pasta has over 1 minute left on the timer, turn off the heat and wait. Otherwise, add the ¾ cup cream and turn up the heat to bring it to a boil.
¾ cup cream
Transfer the spaghetti straight into the nori cream sauce with tongs when it is done. Toss the pasta in the sauce and let it finish cooking. Add more pasta liquid to keep it loose and slippery if it starts sticking together.
Return the shrimp to the pan along with the chopped 25 grams watercress and toss to combine.
25 grams watercress
Plate the shrimp pasta by twirling it onto two plates and then garnish it with the watercress tips.