In a large skillet with tight-fitting lid, melt the butter over medium-high heat. Add the chopped onion and saute for 3-5 minutes.
Add in the frozen peas and saute for 2-3 minutes. Add in the chopped ham and combine together.
Add in the dry penne pasta noodles. Pour in 2 cups of chicken stock and the heavy cream. Stir to combine. Stir in the remaining chicken stock, until the pasta noodles are all "under water." Add more water or chicken stock to cover the pasta. Press pasta into the liquid.
Put the lid on the skillet and reduce heat to medium and let simmer for 8 to 11 minutes, or until pasta is cooked through.
Once cooked, add salt and pepper and the grated Parmesan. Remove from heat and stir together. Sauce will thicken as it cools. Garnish with shredded or grated Parmesan cheese.
Serve Penne & Ham Skillet as one-dish meal, or with side salad or veggies.