Add butter to large skillet over medium heat. Add chopped pancetta to pan and cook until it begins to brown. Remove pancetta from pan. Add onion to pan and cook until onion becomes translucent, then stir in garlic and cook for another couple of minutes.
Beat eggs into heavy cream with lots of ground pepper, Parmesan cheese and most of parsley. Set aside.
Meanwhile, cook pasta according to package directions for al dente. Drain pasta, saving about a cup of pasta water. Still over medium heat, add hot pasta along with about 1â�„4 cup of the reserved pasta water to pan with onions and mix with tongs. Immediately add egg mixture and reserved bacon and combine well with tongs. Add more of the reserved pasta water if needed while tossing.
Garnish with reserved parsley and extra Parmesan, and serve immediately.
(This recipe was contributed as part of a "Cook of the Week" feature.)