Place the slices of bacon in a cold pan and fry for about 2 min. over a high heat, then reduce the heat and cook until golden and crispy. Let the bacon drip off on some kitchen towel, then break the crispy bacon into small pieces. Wipe off the pan. Pour the cream into the pan, add salt and pepper and bring to a boil. Mix the eggs with 75g of the cheese in a bowl.
Combine the tomatoes, onions and oregano. Season with salt and pepper.
Meanwhile, bring salted water to a boil in a large heavy-bottomed pot. Cook the spaghetti for 8-10 min. until tender but not overcooked. Drain the spaghetti in a colander, then return it to the pot. First stir the warm cream mixture into the spaghetti, then add the bacon and the egg-cheese mixture. Season to taste and serve immediately with the rest of the cheese and a tomato salad.