Cook pasta according to manufacturer manual (it is better to use pasta with some kind of hole).
In the meantime cut pancetta into very small cubes and fry it until almost crisp (if you use Teflon pan you doni 1/2t need olive oil, pancetta has enough fat, if not, use some olive oil).
Mix egg yolk, sour cream, grated parmesan and parsley into mixture and wait.
When the pasta is ready, add oregano and pepper into pan, heat it and now make pancetta crispy, add pasta, stir a bit and than add parmesan mixture into pan.
Stir not longer than 1 minute and serve.
You may add freshly grated parmesan onto meal as well.