Cook the pasta in salted boiling water until al dente.
In a large sauté pan brown the sausage in the olive oil. About 7-10 minutes.
With a slotted spoon transfer it to a plate leaving the rendered fat in the pan. Set aside.
Add the onions to the pan and cook until the edges start to brown.
Add the wine and reduce.
Add the peas and cook for 2 minutes. Add salt to taste.
Add the sausage back into the pan and sauté all together for about 5 minutes. Add the al dente pasta and mascarpone and toss together.
Finish with fresh ground black pepper.