Preheat the oven to 200°F. Place your pasta bowls on a baking sheet and place them in the oven to warm until ready to serve.
Bring a pot of salted water to a boil.
Pat the shrimp dry with a paper towel and then sprinkle both sides with salt and pepper.
Heat 2 tbsps of the butter over medium-high heat in a large (12-inch) skillet. Add the garlic, cut-side down, and swirl around with the help of a wooden spoon in the butter until aromatic, about 1 to 2 minutes. Remove the garlic from the butter.
Add the shrimp in one layer, without overlapping, and sauté for 2 minutes, or until turning pink on the underside. Flip and cook for another 2 to 3 minutes, until the shrimp is very pink and curled and cooked through. Use a spatula to transfer the shrimp to a plate and cover with foil to keep warm.
Add the pasta to the water and cook until al dente, usually about 13 minutes.
After the pasta has started cooking, add the remaining 6 tbsp of butter and 1¾ cup of the cream to the same skillet that you cooked the shrimp in. Turn the heat on medium-low and swirl the butter until it melts and is barely simmering. Use your spatula to scrape up any of the bits on the bottom of the pan from cooking the shrimp. Simmer on low for 2 minutes.
Meanwhile, drain the pasta, reserving ½ cup of the pasta water.
Transfer the sautéd shrimp and drained pasta to the skillet with the cream and butter. Use a couple of large spatulas or spoons to coat the pasta completely with the sauce.
Add the grated cheese, 1 tsp of salt, ½ tsp of pepper, and nutmeg (½ tsp) to the pasta and stir to fully incorporate.
Cook for a couple of more minutes. The sauce will thicken as it cooks on low. Thin the sauce slightly with the remaining ¼ cup of cream and a bit of the pasta water.
Carefully remove the warmed pasta bowls from the oven and fill them with the shrimp fettuccine alfredo. Garnish with chopped parsley, if desired.