Bring a large pot of salted water to a boil. Add pasta and cook until al dente.
At the same time, heat oil in a frying pan. Once hot, add the sage leaves and fry until crispy. Set aside ⅓ of the leaves.
Add lemon juice, lemon zest, pasta cooking water and parmesan. Mix well and simmer for 2-3 minutes until creamy.
Drain the pasta and mix with the sauce.
Top pasta with the sage leaves and serve immediately.