Brush a 8x12 inch (20-30 cm) baking dish with olive oil.
In a large deep pan or pot heat 2 teaspoons of olive oil and sauté the spring onions for 2-3 minutes, add the spinach and continue heating until spinach wilts and shrinks. Remove from pan, strain and let it cool.
In a large bowl mix the feta cheese, 2 tablespoons parmesan, 1 tablespoon bread crumbs, oregano, dill, 1 tablespoon olive oil, a pinch of salt and freshly ground pepper. Add the spinach and mix making sure it has spread in the whole mixture.
In a small bowl whip the eggs and add them to the spinach mixture and mix well.
Grease a baking dish with olive oil and transfer the spinach mixture to the baking dish. Even it out and sprinkle over it the rest of the parmesan (2 tablespoons).
Make topping: in a small bowl place the rest of the bread crumbs (3 tablespoons), and add olive oil gradually (do not add all of it at once) while pressing the mixture with a fork, add enough olive oil until you have a crumbly texture and all the breadcrumbs are wet. Sprinkle over the casserole.
Bake in the oven for about 15 minutes. After that, put under broiler about 1-2 minutes until topping is golden (check often).
Let it cool and serve.
You may serve with a squeeze of lemon.
Notes
Make Ahead:
Assemble it the night before (except for the topping), transfer to the baking dish and cover tightly with aluminum foil and place in refrigerator for one night. To Bake: Make the topping and sprinkle and bake. Freeze
You can also assemble and freeze (uncooked) for 3 months. To bake you must let it defrost first.
You can also freeze after cooking and heat when ready to serve.