Cook the pasta in a pot of salted boiling water for 10 minutes, or according to the package instructions, until al dente. Add the peas to the pot for the final 3 minutes of cooking, returning the water to the boil.
While the pasta is cooking, put the pancetta or bacon pieces into a frying pan and fry without fat over a medium heat, stirring occasionally, for 4-5 minutes or until lightly browned and crispy. If necessary, drain off the excess fat from the pan, leaving about 1 tsp (5 mL). Add the scallions to the pan and cook gently for 1 minute or until just soft.
Put the Parmesan cheese into a bowl with the eggs and ricotta cheese. Season with ground black pepper and beat together with a fork.
Drain the spaghetti and peas, and return them to the hot, empty pot with the pancetta or bacon and scallions. Off the heat, add the egg mixture and toss thoroughly so that the eggs thicken in the residual heat to make a creamy sauce to coat the pasta. Turn into a serving bowl and serve sprinkled with more Parmesan cheese.
• Instead of using eggs, ricotta cheese and Parmesan cheese, make a smooth, creamy sauce by heating ¼ lb soft goat cheese with garlic and herbs with 6¾ tbsp 3.25% milk in a small pot, stirring constantly. Toss through the cooked spaghetti with the pancetta or bacon, scallions and peas, and serve immediately.
• Instead of frying pancetta or bacon and scallions, use ¼ lb smoked salmon, cut into thin strips (or use trimmings), and add 2 tbsp snipped fresh chives.