Bring a large pot with a 1/2 inch of water in it to boil. Add spinach, cover, and cook until it just wilts. Cool spinach in cold water, drain well, squeeze as much moisture from it as you can, and then coarsely chop. Combine spinach in a bowl with feta, Parmesan, egg, dill, garlic and salt and pepper to taste. Preheat oven to 375¡F. Brush a sheet of filo pastry lightly with butter. Top with another sheet and brush again. Repeat process until all sheets are used. Spoon spinach mixture, shaping it into a long, narrow rectangle, in the middle of the bottom third of the pastry. Fold over the sides of the pastry. Carefully roll filling into the pastry. Make small cuts at a 45¡ angle into the top of the pastry to make cutting easier when baked. Brush top with a little butter and sprinkle with sesame seeds. Bake for 25-30 minutes, or until puffed and golden. If desired, brown top under the broiler a few minutes. Use a serrated knife to cut into portions.
Note: Spinach is rich in iron, vitamin A and C.