Mix tomato passata and dried oregano in a small bowl and set aside.
Beat eggs in a bowl with a pinch of salt and pepper.
Heat up olive oil in an oven-safe skillet over medium-low heat.
Add beaten eggs and cook, covered, until eggs are set.
Spread tomato sauce all over and top omelette with pepperoni, cheese and olives.
Transfer omelette to oven and cook under grill setting under cheese is golden and bubbly.
Cut into slices and serve immediately. Enjoy!