Preheat oven to 200°Celsius.
Heat oil in a large frying pan over medium heat. Add onion and garlic. Cook, stirring, for 6 minutes or until soft. Remove from heat Add spinach. Cover until just wilted. Transfer to a sieve.Using a wooden spoon, press as much liquid from spinach mixture as possible. Transfer mixture to a large bowl. Add feta, dill, pepper and egg. Season with salt. Mix well to combine.
Place 1 pastry sheet on workbench. Brush with melted butter. Top another sheet of pastry.Continue to layer pastry, to form 6 layers.
Cut the pastry down the middle. Spoon spinach mixture at one end of the pastry Fold the end over the filling to form a triangle, then continue to fold up the strip in triangles, like folding up a flag.
Continue with remaining strips of pastry, placing the filled triangles on the baking sheet and keeping them covered with a towel until all are ready to bake.
Brush with melted butter before baking at 200 C for 10-15 minutes.
For Finger food – Cut filo into 6 widthways – Roll each strip into triangles.