- With the rack in the middle position, preheat the oven to 180 °C (350 °F). Line a baking sheet with parchment paper.
- In a saucepan, soften the onion and garlic in the oil. Add the ground beef, oregano and cook over high heat. With a wooden spoon, break up meat until cook through. Season with salt and pepper.
- Add the spinach and let it wilt. Remove from the heat and let cool. Add the cheese and egg. Stir to combine and adjust the seasoning.
- On a work surface, lay a first sheet of phyllo dough and brush it with melted butter. Cover with two more sheets of phyllo dough and brush with butter. Cut into 12 squares. Place 15 ml (1 tablespoon) of the ground beef mixture in the centre of each square. Fold the two corners perpendicular to the filling into the centre. Fold in the two other corners and then roll to form a small cylinder. Brush with butter.
- Put the rolls on the baking sheet. Bake for about 10 minutes. Serve as hors d’oeuvre.