Cook pasta per package directions, drain and set aside.
In a large skillet over medium heat, add butter and let it melt. Add minced garlic, garlic powder, and salt. Whisk together to combine.
Sprinkle the flour over the butter and garlic mixture. Whisk together and then slowly add the heavy cream and milk while whisking. Let sauce begin to boil and then reduce heat to low and allow it to simmer for 2 to 3 minutes.
Add parmesan cheese and whisk together.
Add the cooked and drained fettuccine. Use tongs to toss the pasta in the sauce.
Garnish with fresh parsley and serve.
Notes
Heating the butter and cream to bubbling so that the cheese melts better when added.
To help make your sauce extra creamy, allow your cheese to come to room temperature before adding it to the sauce.
Alfredo sauce thickens while standing and thickens even more when added to pasta. If it seems too thin, resist the urge to thicken it as it will thicken once mixing it with your pasta.