Cook ½ lb. of spaghetti in boiling salted water. Meanwhile in a large sauté pan over medium heat, crisp 6 oz. pancetta (cubed) and ½ cup finely diced onion in 2 tbsp. butter. Add the pasta to the pancetta and onion, then add 1 cup of chicken stock and 1 tsp. black pepper. Bring the mixture to a boil. Mix 4 egg yolks and 2 tbsp. heavy cream in a small bowl. When the sauce is almost reduced, remove from the fire. Add egg mixture to the pasta, mixing until the sauce is thickened. Finish with parmesan. Mangia!