Bring a pan over medium-high heat and add the butter. Once it’s melted and hot, stir in the mixed garlic for about 20 seconds.
Then immediately mix in the sauce.
Now bring a pot of well-salted water to a boil and cook the spaghetti noodles al dente. Make sure not to drain the pasta water since you will need some of it for the sauce.
Add the cooked noodles straight from the pot of water to the pan of sauce. The pasta will carry over a little bit of hot pasta water which will add extra starch to make the sauce a little thicker and adhere to the spaghetti better.
Then add the freshly grated Parmesan cheese. Mix well and garnish with chopped green onion. Tip: buying a block of parmesan and grating the cheese into fine shreds will give you a smoother sauce vs buying already grated cheese.