Болонское рагу

Peel the onion, scrub the carrot, then very finely chop along with the celery. Finely chop the pancetta.Melt the butter with 1 splash of olive oil in a large pan over a medium heat.Fry the pancetta for 1 minute, then add onion, carrot and celery and cook for 10 minutes, or until starting to soften.Add the mince and fry for 5 minutes, or until lightly browned all over and any liquid has evaporated.