Heat 1 tbsp of olive oil in skillet on high heat then add mushrooms.
Sauté mushrooms on high heat until golden (3-5 minutes).
Make sure to keep an eye on the mushrooms, you will need to sauté the mushrooms on a high heat to avoid the collection of fluid in the pan, but you mustn't allow the mushrooms to stick to the bottom of the skillet.
Once mushrooms golden, transfer to a paper towel lined bowl. The paper towel will soak up any juices that are released.
Cook pasta al dente as directed on the packaging.
Drain pasta, but collect the water from the pasta and return to saucepan and place on a low heat to simmer.
Shake of excess water from pasta and then drizzle with remaining tbsp of olive oil.
Shake around so that olive oil coats all of the pasta, then set aside.
Place heat proof bowl on top of simmering saucepan.
Once bowl is warm add ricotta sauce ingredients.
Whisk ingredients together until sauce is very warm and smooth.
Lower heat under pan to its lowest to keep sauce warm.
Place pasta, mushrooms and 1/4 cup of walnuts into a bowl.
Shake ingredients around until thoroughly mixed then turn off heat under pan.
Add ricotta sauce to pasta, mix, and serve immediately.
Sprinkle with remaining walnut pieces.