Cook the noodles according to the package directions, minus 1 minute. They will cook a little more in the sauce so you don’t want them overcooked.
Heat 2 tablespoons of butter in a large saute pan. Season the shrimp with salt and pepper and add to the hot pan. Cook for 2 minutes until it turns pink, then flip over and cook the other side till it turns pink for about 2 minutes. Remove from the pan.
Add the remaining butter to the pan and cook the garlic for 2 minutes, whisk in the cream, making sure it doesn’t heat too quickly and curdle.
In a small bowl, whisk a half cup of the hot spaghetti water into the egg, then set aside.
Add the parmesan cheese to the hot cream and stir till melted, turn on low. Slowly whisk in the egg, making sure not to curdle. Remove from the heat.
Add the noodles and toss to coat, add the shrimp and garnish with parsley.