Heat large pot of water to boiling
Once boiling add 2-3 tablespoons of kosher salt
In a large, deep skillet heat olive oil and pancetta over medium heat
Cook pancetta until fat is rendered and pork is crispy
Remove cooked pancetta from pan and place on paper towel lined plate
To same skillet, add leeks, mushrooms, salt and pepper. Saute for about 8 minutes until leeks and mushrooms are soft
Meanwhile, add pasta to salted, boiling water and cook until al dente (still a bit firm)
To the skillet with the leeks and mushrooms, now add the cooked pancetta, peas, garlic and half n half and saute for about 3-4 minutes.
Turn heat off and add grated lemon rind, lemon juice and cooked pasta to the skillet.
Gently toss pasta in sauce...be sure to add additional HOT pasta cooking water to the pan until you have a silky, smooth sauce.
Place pasta into bowls and top with freshly chopped parsley.