Cook pasta in salted boiling water. Meanwhile, wilt the spinach in boiling water for a couple of minutes, remove from the water and drain. If you have a blender whiz the spinach and crème fraiche.
Add the lemon juice to the spinach mixture and some fresh herbs if you have any.
Boil peas for around 3 minutes and then add them to the sauce and pasta mix it all together with grated cheese on top.