I don't recall when I first came across Carbonara pasta sauce. If my memory serves me well I don't think we ate it when we lived in Italy as young children, only as a favourite tea served by my mother to me and my starving twin brother in our teenage years.
The availability of ingredients dicates what I put into it in each time, but below is my list of ideal ingredients. I'm sure some will scream that this is not an authentic Italian dish but this is what Carbonara sauce has come to be in our house and it now seems a firm favourite of my seemingly starving children.
4 rashers of smoky bacon (or handful of smoked ham or lardons)
2 tbsp double cream
Small handful cheddar (or parmesan if you have it)
1 small garlic clove
Fry the roughly chopped bacon in a little olive oil. I then put the bacon and the rest of the ingredients into a mini food processor to make a smoothish sauce to coat the pasta in an attempt to fool my children that there is really nothing on the pasta. If not using a food processor, finely chop the garlic and beat together with the egg, grated cheese, cream and bacon pieces.
When the pasta is cooked, drain, toss in a little olive oil and black pepper, then put the pasta back in it's cooking pan and mix in the eggy mixture. The heat of the pasta should be sufficient to start to cook the egg. If wary of eating uncooked eggs, you can put the pan back on a very low heat and toss gently until the egg has coated all the strands of pasta and set.