The only, maybe difficult thing here is to find the ready fill pasta. It is easily found in international groceries stores (if you have any close by). If you swap to puff pastry do not roll them out. Just make normal triangles and seal them with some beaten egg yolks.
Ready in 1 hour
1.5 kg fresh spinach
1 big onion
300 grams feta cheese
2 rolls of fillo dough (500 grams)*
3 tbs olive oil
70 grams of butter
You can find the fillo dough easily at international supermarkets.
Put clean spinach in a casserole with 1 tbs of olive oil (no water needed), bring to a boil on medium heat and let them cook until tendere (it should take 10/15 minutes according to spinach quality). Drain, let cool and chop them roughly.
Chop finely the onion and fry it in a casserole with 2 tbs olive oil. When tender, add the spinach and let fry for 6/7 minutes (until the exceeding water is absorbed).
Pour in a container, let cool down, then add the eggs and feta cheese (crushed), mix well, season with salt and set aside.
Unroll the fillo dough, cut stripes of 10×30 cm each.
Brush one of them with the melted butter and couple it with another stripe (2 sheets per spanakopita).
Put a tbs of filling and roll them up in the form of triangles.
Go on with the same procedure, until you finish dough and filling.
Brush them on top with the melted butter and bake for 30 minutes at 180° (if they get too brown, cover them with an aluminium foil).