Cook the spaghetti in a saucepan with enough water until al dente.
In the meantime, dice the onion and fry in a little olive oil in a large pan. Add the thawed spinach and wait until it is completely thawed. Then add the cream cheese and pour in the milk or cream (use a little more if necessary). Season to taste with nutmeg, salt and pepper.
Put the cooked pasta in the sauce and mix everything well.
Meanwhile, in a separate pan, fry the cherry tomatoes in a little olive oil until they burst a little. Season with salt and pepper.
Arrange everything on plates and sprinkle with parmesan.