1. Gently brush off any dirt from the taro root. Then, peel it and pat it dry with a towel (do not wash it!). Insert the knife into the root and break it into small pieces (this is called 'tsakrate' – the secret is to break it, not cut it).
Next, peel the potatoes, cut them into quarters, and then into small pieces/chunks roughly the same size as the taro. Rinse the celery and cut it into thick slices.
In a large pot, add the olive oil and when it heats up, sauté the onion. Afterwards, add the taro and sauté for 1-2 minutes. Then, add the potatoes and celery and stir 2-3 times.
Place the tomato paste at the bottom of the pot and stir so it releases its aromas. Add the salt and pepper. Pour in the hot water and cover the pot. When the water boils, reduce the heat and simmer for 1 hour. Open the pot and season with salt and pepper. Pour in the lemon juice and simmer for another 5-10 minutes or until the sauce thickens. If the taro is not cooked, add a little more water and continue boiling until the taro softens.