1Cook sausages in a large saucepan over medium-high heat until browned and crumbly, about 10 minutes. Place sausages in a bowl. Drain pan, reserving 1 tablespoon drippings in pan.
2Add onion to saucepan. Cook until golden, about 5 minutes. Add cream. Simmer until slightly reduced, about 5 minutes. Add broth. Simmer until thickened, about 5 minutes.
3Return sausage to saucepan. Bring to a simmer. Add peas and mascarpone. Cook, uncovered, until peas are tender, about 5 minutes.
4Meanwhile, cook pasta according to package directions. Drain. (A quick and easy way to cook the penne is to use a colander, large strainer or French-fry basket that fits down inside the pot of boiling water. That way, you can simply lift the basket out and shake it to drain off the cooking water). Combine pasta and sauce in a large serving bowl. Add Parmesan, salt and pepper. Stir to blend. Serve immediately.
Mascarpone, a creamy, mild Italian cheese, isn't always available at the market we frequent. So sometimes we use a mixture of 6 tablespoons cream cheese and 5 tablespoons whipping cream and achieved the same rich results.