- Gently heat the oil in a heavy-based pot.
- Add the finely diced vegetables, stirring gently all the time. After a couple of minutes, season with salt and pepper. Optional extras: finely diced fennel bulb, leek or capsicum. Continue to cook until the vegetables are really soft and almost broken down into a paste. Remember, don't rush this stage - this is where you put TLC into the dish and you will be rewarded later.
- When the ingredients start to stick to the pan, add the juice or wine and continue to stir for a couple of minutes. The mixture is now ready to use as a base for other dishes.