Bring a large pot of salted water to a boil (I use ½ to 1 Tablespoon of salt). Add pasta and cook according to package instructions (usually 10-12 minutes). Before draining the noodles, use a handled glass or measuring cup to scoop out about ½ cup of the starchy pasta water to use later on in the recipe.
While water comes to a boil and pasta cooks, bring a large skillet to medium heat. Once hot, add oil to pan.
Sauté mushrooms and shallot in oil for about 5 minutes until shallot is soft and mushrooms have released most of their water and most of the excess liquid is cooked off.
Add garlic and sauté for another 30 seconds to a minute.
Add white wine, deglazing the pan and scraping up any cooked on pieces of mushroom and onion while it cooks down (about 1 minute).
Slowly pour in heavy cream and stir to coat veggies. Once cream is warm, add in about ¼ cup of parmesan, stirring to melt in. Once melted, add in another ¼ cup of parmesan and stir or whisk in. Save the remaining ¼ cup to garnish the top of each serving.
Stir in peas, lemon zest, salt and pepper and stir for about a minute until peas are mostly cooked.
Reduce heat to low and stir in lemon juice while whisking to prevent curdling.
Add cooked pasta into pan with veggies and sauce, stirring to coat noodles.* Add reserved pasta water, 2-3 tablespoons at time, stirring between each addition.
Slowly fold in smoked salmon and serve, topping each bowl with the reserved parmesan, a heavy sprinkle of fresh dill and fresh cracked black pepper on top.