Radiatore with Sausage Marinara and Mozzarella

I got this recipe is from "The Ladies Home Journal: 100 Great Pasta Recipes". It has, of course, been altered. :) The main changes that I've made were to double the amount of sausage to 1 pound, change the spaghetti sauce to tomato sauce (and use more of it), and to add some garlic. Although the recipe doesn't reflect this, I also use plain sausage rather than italian sausage, and also add 1 1/2 tsp of italian seasoning. I do this because most of the italian sausage that I find at stores has fennel seed in it, and I really don't like that flavor when it comes to sausage.


Ingredients
1 pound sweet Italian sausage
1/2 cup chopped onion
1 large can tomato sauce (29 oz.)
2 cloves garlic, minced
1 pound radiatore (fusili is great too)
8 oz mozarella cheese, diced

Instructions
Prepare pasta per directions on package. Meanwhile, cook the sausage in a large skillet, stirring occasionally and breaking it up. Continue until meat is browned, about 7 minutes. Then add the onions and garlic and cook for 5 minutes more. Add sauce and wait until just starts to bubble. Remove from heat and add the mozarella. Add the pasta to the skillet and stir to combine. Warning: I use a large skillet so there is room to do this. If your pan is too small to hold it all...well, you'll figure it out. :)