1. In a pan, heat the olive oil. Add the pumpkin dice and cook for 5 minutes. Set aside.
2. In a large bowl, beat the eggs and milk into an omelette. When they are well whisked, season with salt and pepper.
3. In a non-stick pan, melt the butter. Pour in the beaten eggs and cook the omelette over medium heat, bringing the eggs from the edges to the center so that the mixture cooks evenly.
4. Place the pumpkin cubes on the entire surface of the omelette. Sprinkle with coriander. Cover and remove from heat; let stand for 3 minutes.
5. Serve the entire omelette in the center of the table.