Heat a large serving dish or bowl. Cook the spaghetti in a large pan of boiling salted water, adding 1 tablespoon of the oil. When the pasta is almost tender, drain in a colander. Return the spaghetti to the pan, cover and leave it in a warm place.

While the spaghetti is cooking, heat the remaining oil in a frying pan (skillet) over a medium heat. Fry the onion until it is translucent, then add the garlic and bacon and fry until the bacon is crisp.

Remove the onion, garlic and bacon with a slotted spoon and set aside to keep warm. Heat the butter in the pan and fry the mushrooms for 3 - 4 minutes, stirring them once or twice. Return the bacon mixture to the mushrooms. Cover and keep warm.

Stir together the cream, the beaten eggs and cheese, and season with salt and pepper.

Working very quickly to avoid cooling the cooked ingredients, tip the spaghetti into the bacon and mushroom mixture and pour on the eggs. Toss the spaghetti quickly, using two forks, and serve it at once. If you wish, serve with extra grated Parmesan.