Bring a large pot of water to the boil and cook pasta until al dente.
Heat a pan over a medium-high heat and cook the spinach with a drizzle of olive oil until wilted.
Remove it from the pan and finely chop it.
Return the chopped spinach back into the pan and on a low heat add the sour cream, a pinch of salt, and mix until a sauce forms.
Add the lemon zest and smoked salmon to the sauce.
Add the pasta to the sauce with a little of the pasta water, and toss together with the parmesan.
Serve with freshly cracked pepper.
