1Onion is optional. I love onion myself, but this will taste fine without it. I used leftover angel-hair pasta, pulled apart into 3-inch pieces. I don't use salt; feta cheese is plenty salty by itself.
2Tear spinach into little pieces.
3Heat oil in the frying pan (I use an 8-inch cast iron pan). Cook onion to desired doneness. I like mine a bit golden, if I'm using onion.
4Combine egg, spinach, noodles, and crumbled cheese in a bowl or large mug. Beat them with a fork until everything is well-incorporated and covered in egg.
5Turn egg mixture into the heated pan. Cover the pan so the patty will cook through before the bottom burns.
6Cook for 5-7 minutes on one side, then turn and finish cooking on the other side.