Add the garlic, 4 Tablespoons of the butter and then the entire box of pasta.
Add salt and pepper (to taste, I like to start with about ½ teaspoon and then add more later as needed)
Bring the entire pan to a boil and cook, stirring frequently, until the pasta is cooked through. You should still have some liquid left.
Turn off the heat and stir in the Parmesan cheese and additional 2 Tablespoons of butter until everything is creamy and combined.
Taste and then add more salt and pepper to your taste.
Serve immediately
Notes
If then liquid seems like it is getting absorbed to quickly, and the pasta is still not cooked, add a little bit additional water or half and half (about ¼ cup at a time). You are better to have a little too much liquid than not enough, so that you end up with a creamy pasta in the end.