Preheat oven to 375
In a medium bowl, combine the two beaten eggs + a pinch of nutmeg (if using) with the crumbled feta – thoroughly coating it. Cover and set aside in the fridge.
Heat a large frying pan on medium heat. Add 2 tablespoons of olive oil to the pan.
Sauté the onion until softened. Add chopped dill and combine until wilted slightly.
Add all the spinach to the pan. It’ll have a lot of volume but will cook down dramatically. Add gradually if needed. Carefully fold to combine with onions and dill until wilted.
Add a little salt and adjust if needed. Note: Your spinach needs to be flavourful on it's own but Feta is salty so take that into consideration when seasoning.
Remove greens from heat (drain out any excess liquid) and set aside to cool.
Note: Either drain by pressing the liquid out in a colander or place greens in a clean dish cloth and ring out.
Lay your stack of phyllo dough sheets on the counter or cutting board and cover promptly with a damp cloth to keep the sheets hydrated. They dry out so quickly so when you take a sheet, cover the rest with the cloth immediately.
When filling is cool, combine the egg/feta mixture with it until evenly incorporated. Set aside.
Butter a 9x13 casserole dish. Place your first phyllo sheet into it and brush it with butter. (a little overhang is ok, you can fold it all onto the filling later.)
Repeat with 3 more sheets, buttering each one. (4 sheets total)
Fill your casserole with the filling, evening it out without compacting it.
Fold any overhanging phyllo over the filling and brush with butter. Crinkles and folds are more than ok here. They contribute to the crispness.
Place 3-4 sheets over the top, brushing them individually with butter as you did for the bottom sheets. Seal it by tucking the top sheets underneath the pie. Alternately, you can place the sheets over the filling and then fold the overhanging sheets over them, brushing the folds down with butter. (It won't look beautiful now but when it's cooked, it will look lovely & rustic ;)
Some people pre-cut their pieces, cutting through the top and filling but NOT cutting through the bottom crust. Alternately, leave it whole but cut a few slits into the top layers for moisture to escape.
Once it’s completely cool, you can freeze it at this point. Otherwise bake for 30-40 minutes (depends on size) until phyllo is crispy and very golden. Enjoy!