I melt 1 stick of butter in a saucepan, add 2 cloves minced garlic and let it simmer on low for a bit to infuse the flavor. Then I add 1 pint of heavy whipping cream and warm over medium heat, once hot I slowly fold in 1 cup of freshly grated Reggiano (it not freshly grated it doesn't melt as well). It will seem a little thin at first, but thickens in a few minutes. Finish it off with several grinds of white pepper and a pinch of nutmeg and pour over hot fettuccini noodles.
I find that the timing of all of this works out really well with the cook time of pasta (3min). When I add my fresh pasta to the water at the same time I add my garlic to the butter, dinner is less than 5 minutes from being on the table.
This is a very rich and creamy sauce, just what you were looking for I believe. Thinking about it makes my mouth water and my gallbladder hurt at the same time.
Dump some shrimp scampi on top of this and I am in heaven.