Bring a pot of water to a boil and cook spaghetti as you prefer. Do not salt the water.
Heat olive oil in a saut pan on low to medium heat. Add garlic and saut lightly until just golden.
Add red pepper flakes and saut briefly.
Add butter to the pan and deglaze.
Add pasta water and heat to combine flavors.
Add tamari and oyster sauce. Heat and stir to combine flavors.
Drain pasta and reserve 1/2 cup pasta water just in case it is needed. Add drained pasta to the saut pan and combine and heat until sauce is adhering to the spaghetti and glistening.
Add chopped parsley and combine until just wilted.
Divide into pasta bowls, top with parmesan cheese and serve.
