Heat vegetable oil in a large skillet over medium heat.

Saute the chopped onion in the hot oil until softened and translucent.

Add ground beef to the skillet and season with marjoram, salt, and pepper.

Stir to break up the meat as it cooks, browning evenly.

Drain off any excess fat from the skillet.

Add chopped spinach to the skillet and cook until it wilts.

Pour well-beaten eggs into the skillet.

Stir continuously, cooking until the eggs are set and cooked through.