Fill a large pot with water and season with lots of salt so that you
can taste it. Bring to a boil. Add the linguine and cook until al
dente, so that it's still firm, and not quite cooked through. While it
cooks, finely grate a handful of cheese into a large serving bowl.
Zest the lemons into the bowl. Scoop out about 1 cup of the pasta water
and reserve. Juice one of the lemons and reserve.
When the pasta is cooked, drain it and tip it into the serving bowl
with the cheese and lemon. Working quickly, sprinkle over the lemon
juice and a little pasta water. Add the creme fraiche, then begin to
fold all of the ingredients together. Fold over again and again until
the pasta is slicked with sauce, the cheese is melted, and the flavors
harmonized. Season with pepper. Taste a strand of pasta. Add more
lemon juice, salt, pepper, and creme fraiche, as desired. If the sauce
is too sticky, add a little more pasta water and mix again.