On the stove bring a large pot of water to boil. While the water is heating, add butter to a large skillet set over medium-low heat. Once the butter has melted add the minced garlic to it and sauté for 1 minutes.
Add the cream to the butter and mix in the nutmeg, black pepper, basil, and parsley.
Stir often as the cream heats and starts to thicken. Adjust the temperature so that the sauce doesn't reach the boiling point or that it bubbles too much.
Once the water pot is boiling, add a bit of salt to the water then the frozen tortellini. Cook according to package directions, about 3 minutes.
Add the frozen peas to the pasta water when there's 1 minute remaining of tortellini cook time.
Drain the water and return the tortellini and peas to the pot. Set aside.
Add the grated Parmesan cheese to the skillet with the sauce one-half at a time, stirring well after each addition so that it melts.
Once the cheese has melted and the sauce has thickened, add the cooked tortellini, peas, and the cut up prosciutto. Stir to evenly coat.
Serve immediately.