I got this recipe from http://tasteofhomecooking.blogspot.com/ but I made several changes. I'll put my changes in red. I'll add pics the next time I make it. This was fantastic, I will make it often.
1/4 cup extra-virgin olive oil
1 large onion, diced I used 4 cloves of chopped garlic
1/2 pound sweet Italian sausages, preferably without fennel seeds Didn't use this at all
1 pound assorted mushrooms, sliced thin I just diced them
1/2 cup balsamic vinager
1 cup seeded and diced canned plum tomatoes, drained I used a can of plain diced tomatoes and I didn't drain it.
1 cup frozen peas, thawed
Freshly ground black pepper
1 1/2 cups chicken stock
1/2 cup heavy cream
1 cup whole-milk ricotta cheese
1 cup freshly grated Pecorino or Parmesan cheese I used parmesan
Cook pasta according to package directions.
Meanwhile, heat the oil in a wide, heavy skillet over medium heat. Add the onion (garlic), and cook, stirring until wilted, about 4 minutes. Crumble the sausage into the skillet and stir, breaking up the sausage into small pieces as you do, until the sausage is lightly browned, about 5 minutes. I cooked the garlic for a few min and went right on to the next step.
Stir about half (all) the mushrooms into the sausage mixture. Add the remaining mushrooms as those in the pan wilt. I poured in about a 1/2 cup of balsamic vinager and cooked until the vinager reduced. Cook, stirring occasionally, until all the mushrooms are lightly browned, about 5 minutes. If the mushrooms give off liquid, allow time for the juices to boil off before the mushrooms start to brown.
Pour the tomatoes into the skillet, stir in the peas, and bring to a boil. Lower the heat so the sauce is at a lively simmer, season lightly with salt and pepper, and cook a minute or two. Stir in the stock and bring to a boil. Cook until the sauce is lightly reduced, about 5 minutes. Pour in the cream and bring to a boil. Spoon the ricotta into the sauce and stir gently to mix.
If the skillet is large enough to accommodate the sauce and pasta, add the pasta to the sauce in the skillet. If not, drain the pasta, return it to the pot, and pour in the sauce. Bring the sauce and pasta to a boil, stirring gently to coat the pasta with sauce. Remove from the heat and stir in 1 cup grated cheese. Check the seasonings, adding salt and pepper if necessary.