In a blender add the flour and slowly the milk until there are no small balls left. Put the milk in a pot and bring to a boil by stirring continuously. Add the butter, pepper, and nutmeg to your taste.
Take the beschamel off the heat, as it hardened and add 3 eggs and mix until they emulsify. Then add in the feta crumbles and the graviera. I keep graviera for the topping, but the result is almost the same.
I like to cook the easier method for the 'cheese pie' and I leave the phylo on the counter, to dry, till the next day. Before mixing the beschamel with the 'phylo pastry' add all the left butter plus I like to add about 50-70ml olive oil. Then I just smash the phyllo, and into the beschamel with it. Make sure it's completely dry. Otherwise it can stick together and the pie is doomed.
If you want to classically pack the cheese pie, here are many methods, depending on your pot. Make it as you know and make sure to evenly pack it and using the butter asigned for the pie, use a brush and brush all the layers inbetween.
But if you have never doen it before, choose my method so that you wont get any surprises.
Butter a pan you want to use, flour it after and add the filling. Cook for 1 hour at 170C or until golden brown. If you add topping cream and graviera, in the last 15 minutes, take it out, use a fork to pin the pie all around, add the cream and then the cheese. It give it a little extra creaminess and its keeps it from getting dry.
This dish is a great breakfast in Greece or you can order it as an appetizer / starter in taverns.