Thaw phyllo dough in the fridge overnight.
Preheat oven to 175°C / 345°F.
Add 8 eggs to a mixing bowl and beat lightly.
Mix in 1 cup of milk, and the feta cheese. Season with a pinch of salt and the ground pepper.
Combine melted butter with olive oil and set aside.
Lay open the phyllo stack and cover it with a tea towel so it won't air-dry.
Prepare the pan. Grease a 9 x13-inch (33 x 23cm) pan with the melted butter mixture. Add 4 sheets of phyllo cross-like, one on top of the other leaving part of them to hang out of the pan. Every two phyllo you add to the pan brush with the melted butter.
Add ½ of the filling. Using a ladle add spoonfuls of it.
Add one folded phyllo on top (a folded phyllo will fit almost exactly inside the pan). Brush with melted butter (because it's a folded phyllo it's like adding two phyllo at once).
Add another folded phyllo, brush with butter, and add the remaining of the filling.
Keep adding folded phyllos' and brushing with butter until you've used them all.
Overlap and fold the phyllo that hangs out of the pan on top of the pie. Brush well with butter or use olive oil if you have run out of butter.
Scar the top and divide the pie into 8 pieces. Try not to cut all the way to the bottom. If some of the filling comes on top that's okay.
Finish off. In a mixing bowl beat the remaining egg and combine with the remaining cup of milk. Pour it all over the pie.
Bake for 45 to 50 minutes or until the pie is set and gets a nice golden brown color on top. If it gets too puffy you can slice it a bit on top to help it release steam.
Serve and enjoy!