Cook the pasta 10 minutes in salted boiling water to cover, or as directed on package.
Drain.
Meanwhile melt the butter in a heavy, 12-inch iron skillet.
Add the chopped onion and saute about 3 minutes.
Add the sausage and continue to saute, stirring often, about 2 more minutes or until the onion is golden and soft.
Stir in the drained pasta and the Alfredo Sauce.
Sprinkle with Mozzarella.
Place under the broiler for 3 to 5 minutes, or until the top is golden brown and the cheese is melted and gooey.
Serve immediately.
Notes
This recipe has been slightly changed because you can no longer get a pound of sausage - it's been downsized to 12 ounces.Tips-Expert Tip: Use an oven safe skillet when preparing this recipe so that you can put the whole thing straight in the oven when it is ready.
You can assemble this up to a day ahead of time in a baking dish and then just shove the whole thing in the oven for about 30 minutes if the idea of cleaning up after dinner is overwhelming.
Using an iron skillet allows you to put the whole thing in the oven to crisp up the top.
Don't let the sauce come to a boil - it can separate a little. Heat it at a simmer.
Save time by buying chopped onions or chopped onions and Bell peppers in the produce section of your store.
Variations
I like to use spicy smoked sausage because it's a nice contrast with the creamy sauce.
Try cooked Italian sausage instead of smoked sausage - either sweet or hot (or a mixture of the two!).
Of course, cooked, leftover chicken is delicious in this dish.
Add green and red Bell peppers in the pan when you are sautéing the onions for both color and flavor.
Mix up cultures with the addition of some poblano pepper or a little jalapeno.
A few handfuls of fresh, baby spinach is good in this dish.
I like shell pasta because it collects the sauce but penne pasta, fusilli, farfalle, and rotini are good, too.
Use smoked Provolone instead of Mozzarella on the top before broiling.
If you happen to have some cooked broccoli, peas, green beans, or whatever - toss it in.
Use cooked chicken or turkey in place of the sausage.