I make a sauce that sounds like what you are referring to. We use it for a dish that we call "sklillies", it is also good on wheat pasta.
1 lb bacon - cut in small pieces
1 onion diced
1 large container sour cream
Brown bacon pieces and onion until brown, put it in bowl with paper towels to soak up fat.
Put bacon/onion mix back in pan and mix in sour cream, let simmer.
If it gets too thick, just add a little milk.