Cook spinach in a pot of salted boiling water until just wilted, a minute or 2. Strain and cool. While the spinach cools, prepare your large ramekins/enamel mugs. You will need 8. Roll out the puff pastry sheets on a floured surface, thin. Quarter each sheet so you have 8 pieces. Line each ramekin/mug with the pastry sheets so you have enough overhang to cover the top when filled. Prick the pastry sitting inside the vessel with a fork all around. Chill until filling is ready. When the spinach is cool enough to touch, squeeze out all extra water with your hands. Coarsely chop. Preheat your oven to 350°F. Place chopped spinach in a large mixing bowl. Add ricotta, Parmigiano, salt, and pepper to taste. Add 1 egg and stir to incorporate. Fill pastries halfway with the filling, then crack in 1 egg, salt and pepper the egg, and fold the hanging pastry over the top carefully. The vessel should not be over flowing at this point as the egg and filling will puff up and expand when baked. Beat the final egg and brush the top of each pie with the egg wash. Place vessels on a baking sheet, and bake for 25–30 minutes or until lightly browned and crisp. Cool and serve at room temperature.