Put water in a pot to 5cm, add a pinch of salt, bring the water to the boil, then put in the pasta. It should take a minute for the pasta to sink into the water. Then put the lid on (as it will cook a bit faster with the lid on). It should cook for 10 to 15 minutes. While it is cooking --.
Chop the bacon, slice the mushrooms and crush & slice the garlic. Separate the egg white and egg yellow (egg yolk). The egg white is not needed, so can be thrown away.
Put the butter and oil in a frying pan, heat until the butter bubbles. Then put in the mushrooms and bacon. Cook & stir for about two minutes, then put the garlic in, and cook & stir for about another two minutes. (Garlic should not be cooked for more than five minutes - it should not turn brown, or it changes taste and becomes bitter & can spoil the taste of the dish).
Put the fresh cream in the frying pan, and stir with the bacon, mushrooms and garlic for only about 10 seconds. Immediately turn the heat off, add the egg yolk, and immediately stir that in as well. The heat of the cream mixture should cook the egg yolk. Put a good pinch of cracked pepper and either a small pinch of salt or about two heaped teaspoons of finely grated Parmesan or Romano cheese.
Check the pasta is to your liking (take a nibble of a bit), then drain the water and put the pasta straight into the frying pan with the cream, bacon, mushroom mixture. Stir it into the mixture until the pasta is completely covered. Serve, maybe with a small side salad – crisp lettuce and sweet tomatoes.