Lightly fry, or saute the onions before adding to the pot. Then add all the ingredients to your soupmaker, making sure to give them a good stir.
Add the stock, either up to the maximum 1600-1800g for a Soup maker or the full 1 Litre of stock if you are cooking this in a saucepan.
Select the smooth setting for a pureed soup, or the chunky if you prefer some bits in your lentil soup. If you plan to leave your soup chunky, chop your onions and potatoes very finely before adding them to the pot.
Serve with hot fresh bread, croutons, or even oatcakes.