Heat oven to 350°. Line 2 baking sheets with parchment.
Spread asparagus and mushroom slices on one sheet in single layer. Drizzle with olive oil and salt and pepper.
Lay hazelnuts out in single layer on the second sheet.
Roast the 2 baking sheets for 10 minutes.Allow the asparagus and mushrooms to rest on the baking sheet until you are ready to add them to the pasta.Watch the hazelnuts carefully so they don't burn. Turn hot nuts out on to a clean tea towel. Fold the cloth over and gently rub cloth over the nuts and nuts together. Filter out the skins. Don't worry about the odd skin that sticks to a nut. Chop nuts to a medium/fine dice.
Prepare pasta according to package instructions. Drain when done, reserving 1 cup of pasta water. Return pasta to the pot.
Combine ricotta, sour cream and Parmesan until well mixed. Add to the pasta and stir well. If it is too dry add a bit of the pasta water at a time until it is the consistency you want. Add the asparagus and mushrooms. Toss mixture over medium heat until evenly heated through - about 3 minutes.
Mound pasta in a serving bowl and top with hazelnuts, chives and more parmesan if desired. Serve with fresh lemon wedges so each diner can drizzle theirs with fresh lemon juice.