Prepare noodles, from Basic Spinach Pasta Dough.
Heat oil in a medium saucepan.
Add onion and saute over medium heat until pale yellow.
Add pancetta and saute until lightly colored.
Press tomatoes through a food mill or sieve to remove seeds.
Stir tomato pulp into saucepan.
Simmer uncovered 25 to 30 minutes or until sauce reduces to a medium-thick consistency.
Season with salt and pepper.
Fill a very large saucepan two-thirds full with salted water.
Bring water to a boil.
Add noodles.
Bring water back to a boil and cook noodles uncovered until tender but firm to the bite.
Drain noodles and place in a warm deep dish or bowl.
Add sauce and toss gently until mixed.