Cook the pasta in a large pot of salted boiling water until al dente. Drain and reserve 1 cup of cooking water.
Tear Prosciutto in small pieces and crisp up in frying pan in olive oil. Remove from pan and drain on paper towel.
Peel shrimp melt 2 tablespoons of butter in a large skillet/frying pan and cook the shrimp in batches until golden brown and opaque. Season the prawns to taste.
Remove from the pan and set aside.
Add the remaining butter and garlic and cook for a few seconds, until the garlic is fragrant then pour in the cream, lemon juice (start with 2 tablespoons and add more if you wish), parsley and season to taste.
Beat egg yolk, slowly add 3 Tbsp of hot cream, one at a time to egg yolk. Stirring constantly. This is called tempering the eggs. Add egg mixture to frying pan. Allow to simmer over gentle heat until the sauce coats the back of a spoon. Add the shrimp back in and adjust seasoning.
Add the pasta and mix to coat.
Garnish with parsley, crispy prosciutto, and freshly grated parmesan