Cook the spaghetti al dente in boiling salted water according to the package instructions.
In the meantime, carefully peel the lemon zest from the washed lemons with a peeler, making sure to thinly peel the lemon zest. Then cut the peeled lemon zest into fine strips. Cut the peeled lemons in half.
Heat the olive oil in a frying pan over a medium heat and add the lemon strips.
In the meantime, drain the spaghetti, reserving the pasta cooking water. Finely grate the Parmesan.
Add the pasta to the lemon olive oil in the pan and toss briefly. Add the butter and season with salt and pepper mix. Increase the heat a little and mix everything well. Add 1 ladle of pasta cooking water and lemon juice, turn the heat up to high and bring to the boil briefly. Fold the Parmesan cheese into the lemon pasta over a low heat.
Arrange the pasta on plates and garnish with more Parmesan cheese and some lemon zest.
Shopping list for 2 people:
6 tbsp olive oil
2 tbsp butter