Cook the spaghetti according to the directions on the package.
Drain and return to the pot.
Meanwhile, in a large, deep skillet heat the oil over medium heat until hot but not smoking, about 2 minutes.
Stir in the curry paste and cook 1 to 2 minutes.
Whisk in the chicken broth, coconut milk, and water.
Bring to a gentle boil, stirring constantly, over medium-high heat, and cook 2 to 3 more minutes.
Whisk in the peanut butter, fish sauce, sugar, and soy sauce until smooth and creamy.
Toss the suace with the noodles and garnish.
