Cook pasta according to package instructions. Drain and set aside.
Meanwhile, heat a large skillet over medium heat. Add the mushrooms and dry saute until they release their water and the water evaporates, 5-10 minutes.
Add butter and shallot to the pan, stir until butter is melted and shallot starts to soften, about 2 minutes.
Add sausage, cook until sausage starts to brown, 2-3 minutes.
Add spinach, stir in until spinach shrinks down and is fully mixed with other ingredients.
Add pasta and parmesan cheese, stir to combine.
Taste and add more salt if needed, then serve with more parmesan cheese if desired.