In a large bowl, mix flour and a pinch of salt.
Make a well in the center and add eggs.
Gradually incorporate flour into the eggs until a dough forms.
Knead the dough for about 8-10 minutes until smooth.
Wrap the dough in plastic wrap and let it rest for 30 minutes.
In another bowl, combine ricotta, Parmesan, spinach, salt, and pepper.
Roll out the pasta dough into thin sheets.
Cut circles or squares from the dough for filling.
Place a spoonful of filling onto each piece of dough.
Fold the pasta over and seal the edges tightly with water.
Bring a large pot of salted water to a boil.
Cook ravioli for 3-4 minutes until they float to the surface.
Drain and serve with warm marinara sauce.