Bring a large pot of salted water to boil over high heat. Stir in tortellini and cook until pasta is just al dente. Add peas to pot for final 30 seconds to 1 minute of cooking time. (I just defrost my peas or run some warm water over them). While the pasta is cooking in another small pan saute the onions and garlic in tablespoon of butter or oil till soft and set aside.
Drain tortellini and peas in a colander and immediately return to pot. Stir in butter, cream, Parmesan, sauteed onions and garlic and the ham. Season with salt and pepper. Turn stove on to medium heat and cook tortellini mixture, stirring frequently, until butter has melted, ingredients are heated through and sauce has thickened slightly, about 2-4 minutes. Serve immediately.