That's the hardest ingredient to find; you'll have to look at groceries that import Mediterranean food. If you have a hard time finding it, you can use instead
Slice the cheese so that slices have the largest possible surface area and a thickness of 1/3 in. If you cut the cheese too thick, it won't melt all the way through; if it's too thin, it will turn into a liquid before you know it instead of turning hot and soft. It's OK if you end up having multiple pieces.
Whip very well, and pour on a plate
Dip the cheese into the egg (all sides) until a nice layer of the egg has gotten attached to the cheese surface. Pour onto the cheese's surface
The flour will stick onto the egg, and you should make sure there is a nice even layer of flour all around.
In a frying pan, heat up until it's very hot
Then, put in the floured cheese. The flour and egg will fry, forming a golden crust (takes about 2 minutes). Flip it over, so that the other side gets fried, too. Serve hot, with
You typically serve saganaki in the very same pan that you cooked it in (to keep the cheese melted inside the golden crust).