Assemble the ingredients. Crumble the feta cheese and set aside. Slice the mushrooms (if using) and set aside. Dice the onion and set aside.
Beat the eggs with oregano and basil added and set aside.
If using frozen spinach, thaw, drain and squeeze out all of the water. If using fresh spinach like I did, chop and quickly sauté in ½ Tbs. olive oil until wilted. Or chop and add during the cooking process. Either way works at midnight!
Crumble and loosen the ground beef and set aside.
Heat a skillet and add 1 Tbs. olive oil. Add the onion and a pinch of salt. Cook until the onion is a bit tender but not browned. (about 2 minutes) (If using mushrooms, add at the same time as the onions).
Add crumbled ground beef and a pinch of salt & pepper to the skillet and brown stirring occasionally, Try to let the meat sit and develop some caramelization and fond on the skillet. (6-7 minutes).
Add the spinach and cook for another minute.
Add the seasoned beaten eggs to the beef/spinach mixture and cook until the eggs are set, about 1-2 minutes. Add salt and pepper to taste. Top with cheese.