Boil the fettucine as per manufacturer's instructions. While the pasta is cooking, prepare the ingredients for the sauce.
Fry the chopped onions in the oil in medium/high heat.
Add the green onions.
When the onions are golden, add the shrimp.
After the water from the shrimp reduces, add the red peppers.
Add in the mirin.
Mix the flour and water until you have a homogeneous suspension, and pour into the pot with the sauce ingredients.
Add the flavored cream cheese, the ground black pepper, salt and MSG. Allow to simmer until the pasta is ready.
Strain the pasta, place on a plate, and pour the sauce over the pasta..