Cool fettuccine until Al dente. Use package instructions. Save 1/2 cup of pasta water in case needed to thin sauce

Cook shrimp with 2 tbsp butter. Cook until forming a crust and remove from pan.

In same pan, add 4 tbsp butter, all the cream, garlic, and parm cheese. Bring to light simmer

Add fettuccine and mix

Add shrimp and mix. If sauce thickens more than desired, add pasta water. If too thin, let sit for a couple minutes.