Cook the pasta according to directitions on package.
While your pasta cooks, add the olive oil to a large saute pan over medium heat.
Add sage leave strips and (pancetta if using).
Fry for a couple of minutes until the sage and pancetta strips are crispy but not burnt.
Add the lemon juice and whisk. Set aside.
Drain the pasta but leave a fair amount of cooking water in the pasta.
Add the wet pasta to the saute pan and return to heat tossing to coat and thicken the sauce.
Test for seasoning, adding fresh ground pepper and additional salt if desired.