French Pea Soup

Made the French pea soup with mint yesterday but instead of using 20g of butter and a tablespoon of flour I cooked the onion in a tablespoon of olive oil and then added a chopped potato (which acts as the thickener) and the stock and simmered for 15 mins. Then added the frozen peas, mint and sugar and simmered for 5 minutes, then continue to follow the recipe. I did it this way in order to cut out the butter and flour, making it gluten and dairy free (plus lower fat) and having made it both ways, to be honest you cant tell much of a difference.