Cook the pasta following the instructions on the box. Fresh ravioli take between 4 to 6 minutes to cook, so I recommend making the sauce while you bring the water to a boil. Drain the water and set the ravioli aside until you're ready to add it to the sauce.
Make the Alfredo sauce:
Heat a large skillet over medium heat. Melt the butter, add the garlic, and stir to toast it for about a minute, ensuring it doesn’t burn.
Pour in the cream or half and half and milk and stir constantly. Add the grated cheese, salt, pepper, and nutmeg (if using) and combine. Reduce the heat and continue cooking the Alfredo sauce for about 5 minutes.
Combine:
Combine the cooked ravioli with the Alfredo sauce, and serve it with additional grated cheese on top.