Cook the spaghetti until al dente. Reserve a cup of pasta water and set aside. Drain pasta and set aside.
Heat a pan on low to medium heat and add the soft butter. Melt butter.
Add the garlic and sauté until fragrant, then add the Oyster sauce. Do not burn the butter.
Add spaghetti and a cup of pasta water. Stir until all liquid has been absorbed and spaghetti is glossy. Serve immediately.