Press the Sauté key on the Instant Pot (it should say Normal, 30 mins). Add the olive oil, onion, carrot and celery and cook for 4 minutes, stirring a few times.Add the rest of the ingredients and stir. Cancel the Sauté function by pressing Keep Warm/Cancel button.Place and lock the lid, make sure the steam releasing handle is pointing to Sealing. Press Manual (High Pressure) and adjust to 10 minutes. After 3 beeps the pressure cooker will start going.Once the timer goes off, allow the pressure to release for 4-5 minutes and then use the quick release method before opening the lid.Serve with chopped chives or scallions and extra lemon on the side. A dollop of full-fat natural yoghurt or coconut yoghurt (or other vegan option) is gorgeous stirred in.