Heat a heavy-based pan over medium-low heat.
Add a generous amount of extra virgin olive oil (enough to coat the base generously).
Add the finely chopped onion and celery. Sauté until the onion becomes translucent (about 5-7 minutes). Avoid browning.
Stir in the grated carrot. Continue cooking for another 5-7 minutes until all vegetables are soft and fragrant.