Trim stems from spinach leaves, rinse leaves well and place in a large saucepan over medium heat. Cook until leaves are wilted, drain in a colander and cool slightly. Press firmly to remove all excess liquid. Cut spinach finely.
Add onion to a heated greased frypan and stir until onion is soft then stir in the spinach.
Cook until any liquid has evaporated then add ricotta. Continue stirring over heat until spinach and ricotta are combined.
Transfer mixture to a bowl and cool slightly then stir in parmesan. Season with salt and pepper.
Cut pastry sheets in half. Spoon 1/2 cup spinach mixture along one long edge of each pastry strip. Brush the other long edge with egg then roll up to enclose filling and form rolls.
Place rolls seam side down then brush tops with whisked egg and sprinkle with a little extra parmesan if desired.
Cut each roll diagonally into 4 pieces.
Place rolls on a greased oven tray and bake in a 200 degrees C preheated oven for 20-25 minutes until golden.