To make this dish you will need:
2.) Bring a large pot of salted water to a boil, add the pasta and cook according to package directions, drain well. Saving 1/2 cup of the starchy cooking water to use in the sauce, if you wish.
3.) Meanwhile, heat the olive oil in a deep skillet on medium. Add the prosciutto and scallions. Saute for about 3 minutes, until the prosciutto is crisp. Toss the garlic in and saute for less than 1 minute to soften.
4.) Add the hot, drained pasta to the pan and toss for 2 minutes to coat the strands in the fat. Beat the eggs and parmesan together in a mixing bowl, stirring well to prevent lumps. Remove the pan from the heat and pour the egg/cheese mixture into the pasta, whisking quickly until the eggs thicken, but do not scramble (this is done off the heat to ensure this doesn't happen). Thin out the sauce with a bit of the reserved pasta water, until it reaches desired consistency. Season the carbonara with several turns of freshly ground black pepper and salt. Mound the spaghetti carbonara into warm serving bowls and garnish with chopped parsley. Pass more cheese around the table.