Cook pasta in salted water until tender, about 12-13 minutes. Drain and return to pot and put to side if done before sausage mixture. Save ¼ cup of liquid.
Heat 2 tablespoons oil in a large skillet.
Add sausage, breaking up large chunks and cook until browned and crumbly, about 5 minutes.
Add mushrooms and more oil, if needed. Cook until mushrooms are tender, and water has evaporated, about 8 minutes.
Add peas, cook about 3 minutes. Add salt so peas stay bright green.
Add sausage mixture to pasta, stir. Add some of the reserved water. Cook long enough to heat through and meld flavors, about 5 minutes.
Drizzle remaining oil over pasta and add Romano cheese.
Serve with additional cheese.